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  • Wordpress Search Results in Order

    - by Brad Houston
    One of my clients websites, www.kevinsplants.co.uk is not showing the search results in alphabetical order, how do I go about ordering the results in alphabetical order? We are using the Shopp plugin and I believe its that plugin that is generating the results! Cheers, Brad case "orderby-list": if (isset($Shopp->Category->controls)) return false; if (isset($Shopp->Category->smart)) return false; $menuoptions = Category::sortoptions(); $title = ""; $string = ""; $default = $Shopp->Settings->get('default_product_order'); if (empty($default)) $default = "title"; if (isset($options['default'])) $default = $options['default']; if (isset($options['title'])) $title = $options['title']; if (value_is_true($options['dropdown'])) { if (isset($Shopp->Cart->data->Category['orderby'])) $default = $Shopp->Cart->data->Category['orderby']; $string .= $title; $string .= '<form action="'.esc_url($_SERVER['REQUEST_URI']).'" method="get" id="shopp-'.$Shopp->Category->slug.'-orderby-menu">'; if (!SHOPP_PERMALINKS) { foreach ($_GET as $key => $value) if ($key != 'shopp_orderby') $string .= '<input type="hidden" name="'.$key.'" value="'.$value.'" />'; } $string .= '<select name="shopp_orderby" class="shopp-orderby-menu">'; $string .= menuoptions($menuoptions,$default,true); $string .= '</select>'; $string .= '</form>'; $string .= '<script type="text/javascript">'; $string .= "jQuery('#shopp-".$Shopp->Category->slug."-orderby-menu select.shopp-orderby-menu').change(function () { this.form.submit(); });"; $string .= '</script>'; } else { if (strpos($_SERVER['REQUEST_URI'],"?") !== false) list($link,$query) = explode("\?",$_SERVER['REQUEST_URI']); $query = $_GET; unset($query['shopp_orderby']); $query = http_build_query($query); if (!empty($query)) $query .= '&'; foreach($menuoptions as $value => $option) { $label = $option; $href = esc_url($link.'?'.$query.'shopp_orderby='.$value); $string .= '<li><a href="'.$href.'">'.$label.'</a></li>'; } } return $string; break;

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  • hibernate annotation- extending base class - values are not being set - strange error

    - by gt_ebuddy
    I was following Hibernate: Use a Base Class to Map Common Fields and openjpa inheritance tutorial to put common columns like ID, lastModifiedDate etc in base table. My annotated mappings are as follow : BaseTable : @MappedSuperclass public abstract class BaseTable { @Id @GeneratedValue @Column(name = "id") private int id; @Column(name = "lastmodifieddate") private Date lastModifiedDate; ... Person table - @Entity @Table(name = "Person ") public class Person extends BaseTable implements Serializable{ ... Create statement generated : create table Person (id integer not null auto_increment, lastmodifieddate datetime, name varchar(255), primary key (id)) ; After I save a Person object to db, Person p = new Person(); p.setName("Test"); p.setLastModifiedDate(new Date()); .. getSession().save(p); I am setting the date field but, it is saving the record with generated ID and LastModifiedDate = null, and Name="Test". Insert Statement : insert into Person (lastmodifieddate, name) values (?, ?) binding parameter [1] as [TIMESTAMP] - <null> binding parameter [2] as [VARCHAR] - Test Read by ID query : When I do hibernate query (get By ID) as below, It reads person by given ID. Criteria c = getSession().createCriteria(Person.class); c.add(Restrictions.eq("id", id)); Person person= c.list().get(0); //person has generated ID, LastModifiedDate is null select query select person0_.id as id8_, person0_.lastmodifieddate as lastmodi8_, person0_.name as person8_ from Person person0_ - Found [1] as column [id8_] - Found [null] as column [lastmodi8_] - Found [Test] as column [person8_] ReadAll query : //read all Query query = getSession().createQuery("from " + Person.class.getName()); List allPersons=query.list(); Corresponding SQL for read all select query select person0_.id as id8_, person0_.lastmodifieddate as lastmodi8_, person0_.name as person8_ from Person person0_ - Found [1] as column [id8_] - Found [null] as column [lastmodi8_] - Found [Test] as column [person8_] - Found [2] as column [id8_] - Found [null] as column [lastmodi8_] - Found [Test2] as column [person8_] But when I print out the list in console, its being more weird. it is selecting List of Person object with ID fields = all 0 (why all 0 ?) LastModifiedDate = null Name fields have valid values I don't know whats wrong here. Could you please look at it? FYI, My Hibernate-core version : 4.1.2, MySQL Connector version : 5.1.9 . In summary, There are two issues here Why I am getting All ID Fields =0 when using read all? Why the LastModifiedDate is not being inserted?

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  • MySQL - How do I insert an additional where clause into this full-text search (updated)

    - by Steven
    I want to add a WHERE clause to a full text search query (to limit to past 24 hours), but wherever I insert it I get Low Level Error. Is it possible to add the clause and if so, how? Here is the code WITHOUT the where clause: $query = "SELECT *, MATCH (story_title) AGAINST ('$query' IN BOOLEAN MODE) AS Relevance FROM stories WHERE MATCH (story_title) AGAINST ('+$query' IN BOOLEAN MODE) HAVING Relevance > 0.2 ORDER BY Relevance DESC, story_time DESC;

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  • MySQL: Update table column from subquery result

    - by Jhourlad Estrella
    On the Members table are columns "MemberID" and "PointsEarned". I want to update the PointsEarned column from the result of this query: SELECT m.MemberID, m.UserName, ( (SELECT COUNT(*) FROM EventsLog as e WHERE e.MemberID=m.MemberID AND e.EventsTypeID=2)*10 ) + ( (SELECT COUNT(*) FROM EventsLog as e WHERE e.MemberID=m.MemberID AND e.EventsTypeID=3)*3 ) + ( (SELECT COUNT(*) FROM ChatMessages as c WHERE c.MemberID=m.MemberID)*.1 ) as PointsEarned FROM Members as m Can anybody tell me how I should do it with a single query? Thanks!

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  • Does Entity Framework currently support custom functions in the Where clause?

    - by André Pena
    Entity Framework currently supports table valued functions and custom functions defined in the SSDL, but I can't find any example of it being used as a criteria, in the where clause. Example: var query = this.db.People; query = query.Where(p = FullText.ContainsInName(p.Id, "George")); In this example, ContainsInName is my custom function that I want to be executed in the where clause of the query. Is it supported?

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  • How to user IN operator in Linq?

    - by Umapathy
    Query: Select * from pu_Products where Part_Number in ('031832','027861', '028020', '033378') and User_Id = 50 and Is_Deleted = 0 The above mentioned query is in SQL and i need the query might be converted into Linq. Is there any option using the "IN" operator in Linq?. can you convert above mentioned query into Linq?

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  • how to querry on the database without accessing the tables, correct the database but not the tables

    - by user287745
    used is c# sql vs 08 sql server 2005 express whenever and where ever an sql select statement is used, its always like select * from tablename or count statement is alsi like select count something from table name for selecting or doing anything on the tables, i would like to know which tables exits in my the database i am connected to! so like select alltablenames from database_name. please guide.

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  • How to write stored procedure to do this?

    - by chobo
    I would like to create a stored procedure that takes in a string of comma separated values like this "1,2,3,4", and break it apart and use those numbers to run a query on a different table. so in the same stored procedure it would do something like select somefield from sometable where somefield = 1 select somefield from sometable where somefield = 2 select somefield from sometable where somefield = 3 select somefield from sometable where somefield = 4 Thanks!

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  • MYSQL: Udate table column from subquery result

    - by Jhourlad Estrella
    On the Members table are columns "MemberID" and "PointsEarned". I want to update the PointsEarned column from the result of this query: SELECT m.MemberID, m.UserName, ( (SELECT COUNT(*) FROM EventsLog as e WHERE e.MemberID=m.MemberID AND e.EventsTypeID=2)*10 ) + ( (SELECT COUNT(*) FROM EventsLog as e WHERE e.MemberID=m.MemberID AND e.EventsTypeID=3)*3 ) + ( (SELECT COUNT(*) FROM ChatMessages as c WHERE c.MemberID=m.MemberID)*.1 ) as PointsEarned FROM Members as m Can anybody tell me how I should do it with a single query? Thanks!

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  • Sum of a summation in mysql

    - by dames
    I have the following query, in the top select statement (sum(l.app_ln_amnt)/count(l.app_ln_amnt)) works well but in the union I want to find the total of (sum(l.app_ln_amnt)/count(l.app_ln_amnt)) query from the top select statement However my solution seems to be off I need some help please select (sum(l.app_ln_amnt)/count(l.app_ln_amnt)), from receipt_history l UNION select SUM(sum(l.app_ln_amnt)/count(l.app_ln_amnt)), from receipt_history l

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  • I need help with a SQL query. Fetching an entry, it's most recent revision and it's fields.

    - by Tigger ate my dad
    Hi there, I'm building a CMS for my own needs, and finished planning my database layout. Basically I am abstracting all possible data-models into "sections" and all entries into one table. The final layout is as follows: Database diagram: I have yet to be allowed to post images, so here is a link to a diagram of my database. Entries (section_entries) are children of their section (sections). I save all edits to the entries in a new revision (section_entries_revisions), and also track revisions on the sections (section_revisions), in order to match the values of a revision, to the fields of the section that existed when the entry-revision was made. The section-revisions can have a number of fields (section_revision_fields) that define the attributes of entries in the section. There is a many-to-many relationship between the fields (section_revision_fields) and the entry-revisions (section_entry_revisions), that stores the values of the attributes defined by the section revision. Feel free to ask questions if the diagram is confusing. Now, this is the most complex SQL I've ever worked with, and the task of fetching my data is a little daunting. Basically what i want help with, is fetching an entry, when the only known variables are; section_id, section_entry_id. The query should fetch the most recent revision of that entry, and the section_revision model corresponding to section_revision_id in the section_entry_revisions table. It should also fetch the values of the fields in the section-revision. I was hoping for a query result, where there would be as many rows as fields in the section. Each row would contain the information of the entry and the section, and then information for one of the fields (e.g. each row corresponding to a field and it's value). I tried to explain the best I could. Again, feel free to ask questions if my description somehow lacking. I hope someone is up for the challenge. Best regards. :-)

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  • In a C# app, what is the most optimal way to insert many records into sql server?

    - by Otter
    I need to perform a very large sql server insert from a c# application. Somewhere in the range of 20,000 through 50,000 records. What is the fastest way through SQL server to perform the insert? There are several options I know of, but I don't know which is the fastest. insert into MyTable(column1, column2, ..., column*) select 'value','value',...,'value' union select 'value','value',...,'value' VS insert into MyTable(column1, column2, ..., column*) exec('select ''value'',''value'',...,''value''' 'select ''value'',''value'',...,''value''') VS bulk insert from a data file VS Any better way that you know of :)

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  • SQL Syntax for testing objects before creating views & functions

    - by Scott Weinstein
    I'm trying to figure out the syntax for creating a view (or function) but only if a dependent CLR assembly exits. I've tried both IF EXISTS (SELECT name FROM sys.assemblies WHERE name = 'MyCLRAssembly') begin create view dbo.MyView as select GETDATE() as C1 end and IF EXISTS (SELECT name FROM sys.assemblies WHERE name = 'MyCLRAssembly') create view dbo.MyView as select GETDATE() as C1 go Neither work. I get Msg 156, Level 15, State 1, Line 2 Incorrect syntax near the keyword 'view'. How can this be done?

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  • finding if an anniversary is coming up in n days in MySql

    - by user151841
    I have a table with anniversary dates. I want a query that returns me rows of anniversaries coming up in the next 10 days. For instance: birthdate --------- 1965-10-10 1982-05-25 SELECT birthdate FROM Anniversaries WHERE mystical_magical_mumbo_jumbo <= 10 +------------+ | birthdate | +------------+ | 1982-05-25 | +------------+ 1 row in set (0.01 sec) I'd like to keep the query in the form x <= 10, because I'll use that number 10 in other parts of the query, and if I set it to a variable, I can change it once everywhere by changing the variable, and not have to re-write the query.

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  • LINQ to SQL selecting fields

    - by user3686904
    I am trying to populate more columns in the query below, could someone assist me? QUERY: var query = from r in SQLresults.AsEnumerable() group r by r.Field<string>("COLUMN_ONE") into groupedTable select new { c1 = groupedTable.Key, c2 = groupedTable.Sum(s => s.Field<decimal>("COLUMN_TWO")), }; How could I get a column named COLUMN_THREE in this query ? Thanks in advance

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  • Apache-Mina FTPServer Issue — unable to login into apache ftp server while using database user manager

    - by piyush
    I am unable to login into apache ftp server while using database user manager: while entering username and password,I am getting following error in log file: [ INFO] 2013-02-07 20:51:07,779 [] [0:0:0:0:0:0:0:1] RECEIVED: USER piyush [ INFO] 2013-02-07 20:51:07,781 [piyush] [0:0:0:0:0:0:0:1] SENT: 331 User name okay, need password for piyush. [ INFO] 2013-02-07 20:51:07,784 [piyush] [0:0:0:0:0:0:0:1] RECEIVED: PASS ***** [ WARN] 2013-02-07 20:51:07,785 [piyush] [0:0:0:0:0:0:0:1] User failed to log in [ WARN] 2013-02-07 20:51:08,285 [piyush] [0:0:0:0:0:0:0:1] Login failure - piyush [ INFO] 2013-02-07 20:51:08,286 [piyush] [0:0:0:0:0:0:0:1] SENT: 530 Authentication failed. [ INFO] 2013-02-07 20:51:08,286 [piyush] [0:0:0:0:0:0:0:1] RECEIVED: QUIT [ INFO] 2013-02-07 20:51:08,290 [piyush] [0:0:0:0:0:0:0:1] SENT: 221 Goodbye. [ INFO] 2013-02-07 20:51:08,291 [piyush] [0:0:0:0:0:0:0:1] CLOSED here is my xml file ftpd-typical.xml: <?xml version="1.0" encoding="UTF-8"?> <!-- Licensed to the Apache Software Foundation (ASF) under one or more contributor license agreements. See the NOTICE file distributed with this work for additional information regarding copyright ownership. The ASF licenses this file to you under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0 Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License. --> <server xmlns="http://mina.apache.org/ftpserver/spring/v1" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:beans="http://www.springframework.org/schema/beans" xsi:schemaLocation=" http://mina.apache.org/ftpserver/spring/v1 http://mina.apache.org/ftpserver/ftpserver-1.0.xsd " id="Prometheus"> <listeners> <nio-listener name="default" port="2121" /> </listeners> <db-user-manager encrypt-passwords="salted"> <data-source> <beans:bean class="org.apache.commons.dbcp.BasicDataSource" > <beans:property name="driverClassName" value="com.mysql.jdbc.Driver" /> <beans:property name="url" value="jdbc:mysql://localhost/apache_test" /> <beans:property name="username" value="amy" /> <beans:property name="password" value="piyush" /> </beans:bean> </data-source> <insert-user>INSERT INTO FTP_USER (userid, userpassword, homedirectory, enableflag, writepermission, idletime, uploadrate, downloadrate) VALUES ('{userid}', '{userpassword}', '{homedirectory}', {enableflag}, {writepermission}, {idletime}, {uploadrate}, {downloadrate}) </insert-user> <update-user>UPDATE FTP_USER SET userpassword='{userpassword}',homedirectory='{homedirectory}',enableflag={enableflag},writepermission={writepermission},idletime={idletime},uploadrate={uploadrate},downloadrate={downloadrate} WHERE userid='{userid}' </update-user> <delete-user>DELETE FROM FTP_USER WHERE userid = '{userid}' </delete-user> <select-user>SELECT userid, userpassword, homedirectory, enableflag, writepermission, idletime, uploadrate, downloadrate, maxloginnumber, maxloginperip FROM FTP_USER WHERE userid = '{userid}' </select-user> <select-all-users>SELECT userid FROM FTP_USER ORDER BY userid </select-all-users> <is-admin>SELECT userid FROM FTP_USER WHERE userid='{userid}' AND userid='admin' </is-admin> <authenticate>SELECT userpassword from FTP_USER WHERE userid='{userid}'</authenticate> </db-user-manager> </server>

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  • MX records not correctly updated by the Google DNS servers

    - by Mac_Cain13
    We are currently losing some e-mail and we discovered that this is caused by a wrong DNS setting. We used a CNAME for our MX record an thats not allowed. So about 2 weeks ago we changed it to an A-record to fix the problem. It seems all major DNS services (like OpenDNS and ISPs) have synced their records and are returning correct results on our DNS queries. But Googles DNS service (at 8.8.8.8) is still returning the CNAME values and we still some e-mails are not delivered correctly. Query on OpenDNS: ; <<>> DiG 9.7.3-P3 <<>> mx wrep.nl @208.67.222.222 ;; global options: +cmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 51231 ;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 0 ;; QUESTION SECTION: ;wrep.nl. IN MX ;; ANSWER SECTION: wrep.nl. 3595 IN MX 10 druif.wrep.nl. ;; Query time: 21 msec ;; SERVER: 208.67.222.222#53(208.67.222.222) ;; WHEN: Fri Nov 25 21:36:58 2011 ;; MSG SIZE rcvd: 47 Query on Google DNS: ; <<>> DiG 9.7.3-P3 <<>> mx wrep.nl @8.8.8.8 ;; global options: +cmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 12124 ;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 1, ADDITIONAL: 0 ;; QUESTION SECTION: ;wrep.nl. IN MX ;; ANSWER SECTION: wrep.nl. 2372 IN CNAME druif.wrep.nl. ;; AUTHORITY SECTION: wrep.nl. 572 IN SOA ns0.freshdns.nl. hostmaster.twilightinc.nl. 2011112401 14400 3600 604800 3600 ;; Query time: 94 msec ;; SERVER: 8.8.8.8#53(8.8.8.8) ;; WHEN: Fri Nov 25 21:38:10 2011 ;; MSG SIZE rcvd: 117 So is there anyone who can explain why Google is responding with a different (incorrect) result two weeks after the last change? And how can we get Google to update their DNS records correctly? Any help is very appreciated. (Please note that other domains that are managed by the same DNS servers/tools are working fine.)

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  • How to "select file" with Python script? . Google App Engine . Python .

    - by draconisthe0ry
    I'm trying to create an online application for a python function i have created. in my script, i input the path of my file for the computer (input_path = '/users/user/desktop/input.txt') but i'm not sure how to go about this using Google App Engine . I have the choice between 3 templates: flask, django, and bottle . I really do believe this question is relevant for people transitioning from scripts to web-based applications. Do I need to incorporate GUI stuff from Tkinter or something? There has to be a way to simply select a file to use for the input path in an interactive way using python scripts

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  • Can jQuery perform a compound select against the top level only? (a.k.a. "How to avoid chaining chil

    - by harpo
    Basically, is there a way to write a.children('.outer').children('.inner') without the intermediate selector? I can't write $('.outer > .inner', a) because I don't want to do full-depth search against a — I know that the .outer elements are immediate children of a. It's partly a matter of "elegance", but partly because I'm trying to avoid "throwaway" element sets. Yes, jQuery may in effect do the same thing, but it has a better chance of optimizing (at least in theory), when it knows the full query's intent.

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  • Inheritance Mapping Strategies with Entity Framework Code First CTP5 Part 1: Table per Hierarchy (TPH)

    - by mortezam
    A simple strategy for mapping classes to database tables might be “one table for every entity persistent class.” This approach sounds simple enough and, indeed, works well until we encounter inheritance. Inheritance is such a visible structural mismatch between the object-oriented and relational worlds because object-oriented systems model both “is a” and “has a” relationships. SQL-based models provide only "has a" relationships between entities; SQL database management systems don’t support type inheritance—and even when it’s available, it’s usually proprietary or incomplete. There are three different approaches to representing an inheritance hierarchy: Table per Hierarchy (TPH): Enable polymorphism by denormalizing the SQL schema, and utilize a type discriminator column that holds type information. Table per Type (TPT): Represent "is a" (inheritance) relationships as "has a" (foreign key) relationships. Table per Concrete class (TPC): Discard polymorphism and inheritance relationships completely from the SQL schema.I will explain each of these strategies in a series of posts and this one is dedicated to TPH. In this series we'll deeply dig into each of these strategies and will learn about "why" to choose them as well as "how" to implement them. Hopefully it will give you a better idea about which strategy to choose in a particular scenario. Inheritance Mapping with Entity Framework Code FirstAll of the inheritance mapping strategies that we discuss in this series will be implemented by EF Code First CTP5. The CTP5 build of the new EF Code First library has been released by ADO.NET team earlier this month. EF Code-First enables a pretty powerful code-centric development workflow for working with data. I’m a big fan of the EF Code First approach, and I’m pretty excited about a lot of productivity and power that it brings. When it comes to inheritance mapping, not only Code First fully supports all the strategies but also gives you ultimate flexibility to work with domain models that involves inheritance. The fluent API for inheritance mapping in CTP5 has been improved a lot and now it's more intuitive and concise in compare to CTP4. A Note For Those Who Follow Other Entity Framework ApproachesIf you are following EF's "Database First" or "Model First" approaches, I still recommend to read this series since although the implementation is Code First specific but the explanations around each of the strategies is perfectly applied to all approaches be it Code First or others. A Note For Those Who are New to Entity Framework and Code-FirstIf you choose to learn EF you've chosen well. If you choose to learn EF with Code First you've done even better. To get started, you can find a great walkthrough by Scott Guthrie here and another one by ADO.NET team here. In this post, I assume you already setup your machine to do Code First development and also that you are familiar with Code First fundamentals and basic concepts. You might also want to check out my other posts on EF Code First like Complex Types and Shared Primary Key Associations. A Top Down Development ScenarioThese posts take a top-down approach; it assumes that you’re starting with a domain model and trying to derive a new SQL schema. Therefore, we start with an existing domain model, implement it in C# and then let Code First create the database schema for us. However, the mapping strategies described are just as relevant if you’re working bottom up, starting with existing database tables. I’ll show some tricks along the way that help you dealing with nonperfect table layouts. Let’s start with the mapping of entity inheritance. -- The Domain ModelIn our domain model, we have a BillingDetail base class which is abstract (note the italic font on the UML class diagram below). We do allow various billing types and represent them as subclasses of BillingDetail class. As for now, we support CreditCard and BankAccount: Implement the Object Model with Code First As always, we start with the POCO classes. Note that in our DbContext, I only define one DbSet for the base class which is BillingDetail. Code First will find the other classes in the hierarchy based on Reachability Convention. public abstract class BillingDetail  {     public int BillingDetailId { get; set; }     public string Owner { get; set; }             public string Number { get; set; } } public class BankAccount : BillingDetail {     public string BankName { get; set; }     public string Swift { get; set; } } public class CreditCard : BillingDetail {     public int CardType { get; set; }                     public string ExpiryMonth { get; set; }     public string ExpiryYear { get; set; } } public class InheritanceMappingContext : DbContext {     public DbSet<BillingDetail> BillingDetails { get; set; } } This object model is all that is needed to enable inheritance with Code First. If you put this in your application you would be able to immediately start working with the database and do CRUD operations. Before going into details about how EF Code First maps this object model to the database, we need to learn about one of the core concepts of inheritance mapping: polymorphic and non-polymorphic queries. Polymorphic Queries LINQ to Entities and EntitySQL, as object-oriented query languages, both support polymorphic queries—that is, queries for instances of a class and all instances of its subclasses, respectively. For example, consider the following query: IQueryable<BillingDetail> linqQuery = from b in context.BillingDetails select b; List<BillingDetail> billingDetails = linqQuery.ToList(); Or the same query in EntitySQL: string eSqlQuery = @"SELECT VAlUE b FROM BillingDetails AS b"; ObjectQuery<BillingDetail> objectQuery = ((IObjectContextAdapter)context).ObjectContext                                                                          .CreateQuery<BillingDetail>(eSqlQuery); List<BillingDetail> billingDetails = objectQuery.ToList(); linqQuery and eSqlQuery are both polymorphic and return a list of objects of the type BillingDetail, which is an abstract class but the actual concrete objects in the list are of the subtypes of BillingDetail: CreditCard and BankAccount. Non-polymorphic QueriesAll LINQ to Entities and EntitySQL queries are polymorphic which return not only instances of the specific entity class to which it refers, but all subclasses of that class as well. On the other hand, Non-polymorphic queries are queries whose polymorphism is restricted and only returns instances of a particular subclass. In LINQ to Entities, this can be specified by using OfType<T>() Method. For example, the following query returns only instances of BankAccount: IQueryable<BankAccount> query = from b in context.BillingDetails.OfType<BankAccount>() select b; EntitySQL has OFTYPE operator that does the same thing: string eSqlQuery = @"SELECT VAlUE b FROM OFTYPE(BillingDetails, Model.BankAccount) AS b"; In fact, the above query with OFTYPE operator is a short form of the following query expression that uses TREAT and IS OF operators: string eSqlQuery = @"SELECT VAlUE TREAT(b as Model.BankAccount)                       FROM BillingDetails AS b                       WHERE b IS OF(Model.BankAccount)"; (Note that in the above query, Model.BankAccount is the fully qualified name for BankAccount class. You need to change "Model" with your own namespace name.) Table per Class Hierarchy (TPH)An entire class hierarchy can be mapped to a single table. This table includes columns for all properties of all classes in the hierarchy. The concrete subclass represented by a particular row is identified by the value of a type discriminator column. You don’t have to do anything special in Code First to enable TPH. It's the default inheritance mapping strategy: This mapping strategy is a winner in terms of both performance and simplicity. It’s the best-performing way to represent polymorphism—both polymorphic and nonpolymorphic queries perform well—and it’s even easy to implement by hand. Ad-hoc reporting is possible without complex joins or unions. Schema evolution is straightforward. Discriminator Column As you can see in the DB schema above, Code First has to add a special column to distinguish between persistent classes: the discriminator. This isn’t a property of the persistent class in our object model; it’s used internally by EF Code First. By default, the column name is "Discriminator", and its type is string. The values defaults to the persistent class names —in this case, “BankAccount” or “CreditCard”. EF Code First automatically sets and retrieves the discriminator values. TPH Requires Properties in SubClasses to be Nullable in the Database TPH has one major problem: Columns for properties declared by subclasses will be nullable in the database. For example, Code First created an (INT, NULL) column to map CardType property in CreditCard class. However, in a typical mapping scenario, Code First always creates an (INT, NOT NULL) column in the database for an int property in persistent class. But in this case, since BankAccount instance won’t have a CardType property, the CardType field must be NULL for that row so Code First creates an (INT, NULL) instead. If your subclasses each define several non-nullable properties, the loss of NOT NULL constraints may be a serious problem from the point of view of data integrity. TPH Violates the Third Normal FormAnother important issue is normalization. We’ve created functional dependencies between nonkey columns, violating the third normal form. Basically, the value of Discriminator column determines the corresponding values of the columns that belong to the subclasses (e.g. BankName) but Discriminator is not part of the primary key for the table. As always, denormalization for performance can be misleading, because it sacrifices long-term stability, maintainability, and the integrity of data for immediate gains that may be also achieved by proper optimization of the SQL execution plans (in other words, ask your DBA). Generated SQL QueryLet's take a look at the SQL statements that EF Code First sends to the database when we write queries in LINQ to Entities or EntitySQL. For example, the polymorphic query for BillingDetails that you saw, generates the following SQL statement: SELECT  [Extent1].[Discriminator] AS [Discriminator],  [Extent1].[BillingDetailId] AS [BillingDetailId],  [Extent1].[Owner] AS [Owner],  [Extent1].[Number] AS [Number],  [Extent1].[BankName] AS [BankName],  [Extent1].[Swift] AS [Swift],  [Extent1].[CardType] AS [CardType],  [Extent1].[ExpiryMonth] AS [ExpiryMonth],  [Extent1].[ExpiryYear] AS [ExpiryYear] FROM [dbo].[BillingDetails] AS [Extent1] WHERE [Extent1].[Discriminator] IN ('BankAccount','CreditCard') Or the non-polymorphic query for the BankAccount subclass generates this SQL statement: SELECT  [Extent1].[BillingDetailId] AS [BillingDetailId],  [Extent1].[Owner] AS [Owner],  [Extent1].[Number] AS [Number],  [Extent1].[BankName] AS [BankName],  [Extent1].[Swift] AS [Swift] FROM [dbo].[BillingDetails] AS [Extent1] WHERE [Extent1].[Discriminator] = 'BankAccount' Note how Code First adds a restriction on the discriminator column and also how it only selects those columns that belong to BankAccount entity. Change Discriminator Column Data Type and Values With Fluent API Sometimes, especially in legacy schemas, you need to override the conventions for the discriminator column so that Code First can work with the schema. The following fluent API code will change the discriminator column name to "BillingDetailType" and the values to "BA" and "CC" for BankAccount and CreditCard respectively: protected override void OnModelCreating(System.Data.Entity.ModelConfiguration.ModelBuilder modelBuilder) {     modelBuilder.Entity<BillingDetail>()                 .Map<BankAccount>(m => m.Requires("BillingDetailType").HasValue("BA"))                 .Map<CreditCard>(m => m.Requires("BillingDetailType").HasValue("CC")); } Also, changing the data type of discriminator column is interesting. In the above code, we passed strings to HasValue method but this method has been defined to accepts a type of object: public void HasValue(object value); Therefore, if for example we pass a value of type int to it then Code First not only use our desired values (i.e. 1 & 2) in the discriminator column but also changes the column type to be (INT, NOT NULL): modelBuilder.Entity<BillingDetail>()             .Map<BankAccount>(m => m.Requires("BillingDetailType").HasValue(1))             .Map<CreditCard>(m => m.Requires("BillingDetailType").HasValue(2)); SummaryIn this post we learned about Table per Hierarchy as the default mapping strategy in Code First. The disadvantages of the TPH strategy may be too serious for your design—after all, denormalized schemas can become a major burden in the long run. Your DBA may not like it at all. In the next post, we will learn about Table per Type (TPT) strategy that doesn’t expose you to this problem. References ADO.NET team blog Java Persistence with Hibernate book a { text-decoration: none; } a:visited { color: Blue; } .title { padding-bottom: 5px; font-family: Segoe UI; font-size: 11pt; font-weight: bold; padding-top: 15px; } .code, .typeName { font-family: consolas; } .typeName { color: #2b91af; } .padTop5 { padding-top: 5px; } .padTop10 { padding-top: 10px; } p.MsoNormal { margin-top: 0in; margin-right: 0in; margin-bottom: 10.0pt; margin-left: 0in; line-height: 115%; font-size: 11.0pt; font-family: "Calibri" , "sans-serif"; }

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  • Parallelism in .NET – Part 7, Some Differences between PLINQ and LINQ to Objects

    - by Reed
    In my previous post on Declarative Data Parallelism, I mentioned that PLINQ extends LINQ to Objects to support parallel operations.  Although nearly all of the same operations are supported, there are some differences between PLINQ and LINQ to Objects.  By introducing Parallelism to our declarative model, we add some extra complexity.  This, in turn, adds some extra requirements that must be addressed. In order to illustrate the main differences, and why they exist, let’s begin by discussing some differences in how the two technologies operate, and look at the underlying types involved in LINQ to Objects and PLINQ . LINQ to Objects is mainly built upon a single class: Enumerable.  The Enumerable class is a static class that defines a large set of extension methods, nearly all of which work upon an IEnumerable<T>.  Many of these methods return a new IEnumerable<T>, allowing the methods to be chained together into a fluent style interface.  This is what allows us to write statements that chain together, and lead to the nice declarative programming model of LINQ: double min = collection .Where(item => item.SomeProperty > 6 && item.SomeProperty < 24) .Min(item => item.PerformComputation()); .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } Other LINQ variants work in a similar fashion.  For example, most data-oriented LINQ providers are built upon an implementation of IQueryable<T>, which allows the database provider to turn a LINQ statement into an underlying SQL query, to be performed directly on the remote database. PLINQ is similar, but instead of being built upon the Enumerable class, most of PLINQ is built upon a new static class: ParallelEnumerable.  When using PLINQ, you typically begin with any collection which implements IEnumerable<T>, and convert it to a new type using an extension method defined on ParallelEnumerable: AsParallel().  This method takes any IEnumerable<T>, and converts it into a ParallelQuery<T>, the core class for PLINQ.  There is a similar ParallelQuery class for working with non-generic IEnumerable implementations. This brings us to our first subtle, but important difference between PLINQ and LINQ – PLINQ always works upon specific types, which must be explicitly created. Typically, the type you’ll use with PLINQ is ParallelQuery<T>, but it can sometimes be a ParallelQuery or an OrderedParallelQuery<T>.  Instead of dealing with an interface, implemented by an unknown class, we’re dealing with a specific class type.  This works seamlessly from a usage standpoint – ParallelQuery<T> implements IEnumerable<T>, so you can always “switch back” to an IEnumerable<T>.  The difference only arises at the beginning of our parallelization.  When we’re using LINQ, and we want to process a normal collection via PLINQ, we need to explicitly convert the collection into a ParallelQuery<T> by calling AsParallel().  There is an important consideration here – AsParallel() does not need to be called on your specific collection, but rather any IEnumerable<T>.  This allows you to place it anywhere in the chain of methods involved in a LINQ statement, not just at the beginning.  This can be useful if you have an operation which will not parallelize well or is not thread safe.  For example, the following is perfectly valid, and similar to our previous examples: double min = collection .AsParallel() .Select(item => item.SomeOperation()) .Where(item => item.SomeProperty > 6 && item.SomeProperty < 24) .Min(item => item.PerformComputation()); However, if SomeOperation() is not thread safe, we could just as easily do: double min = collection .Select(item => item.SomeOperation()) .AsParallel() .Where(item => item.SomeProperty > 6 && item.SomeProperty < 24) .Min(item => item.PerformComputation()); In this case, we’re using standard LINQ to Objects for the Select(…) method, then converting the results of that map routine to a ParallelQuery<T>, and processing our filter (the Where method) and our aggregation (the Min method) in parallel. PLINQ also provides us with a way to convert a ParallelQuery<T> back into a standard IEnumerable<T>, forcing sequential processing via standard LINQ to Objects.  If SomeOperation() was thread-safe, but PerformComputation() was not thread-safe, we would need to handle this by using the AsEnumerable() method: double min = collection .AsParallel() .Select(item => item.SomeOperation()) .Where(item => item.SomeProperty > 6 && item.SomeProperty < 24) .AsEnumerable() .Min(item => item.PerformComputation()); Here, we’re converting our collection into a ParallelQuery<T>, doing our map operation (the Select(…) method) and our filtering in parallel, then converting the collection back into a standard IEnumerable<T>, which causes our aggregation via Min() to be performed sequentially. This could also be written as two statements, as well, which would allow us to use the language integrated syntax for the first portion: var tempCollection = from item in collection.AsParallel() let e = item.SomeOperation() where (e.SomeProperty > 6 && e.SomeProperty < 24) select e; double min = tempCollection.AsEnumerable().Min(item => item.PerformComputation()); This allows us to use the standard LINQ style language integrated query syntax, but control whether it’s performed in parallel or serial by adding AsParallel() and AsEnumerable() appropriately. The second important difference between PLINQ and LINQ deals with order preservation.  PLINQ, by default, does not preserve the order of of source collection. This is by design.  In order to process a collection in parallel, the system needs to naturally deal with multiple elements at the same time.  Maintaining the original ordering of the sequence adds overhead, which is, in many cases, unnecessary.  Therefore, by default, the system is allowed to completely change the order of your sequence during processing.  If you are doing a standard query operation, this is usually not an issue.  However, there are times when keeping a specific ordering in place is important.  If this is required, you can explicitly request the ordering be preserved throughout all operations done on a ParallelQuery<T> by using the AsOrdered() extension method.  This will cause our sequence ordering to be preserved. For example, suppose we wanted to take a collection, perform an expensive operation which converts it to a new type, and display the first 100 elements.  In LINQ to Objects, our code might look something like: // Using IEnumerable<SourceClass> collection IEnumerable<ResultClass> results = collection .Select(e => e.CreateResult()) .Take(100); If we just converted this to a parallel query naively, like so: IEnumerable<ResultClass> results = collection .AsParallel() .Select(e => e.CreateResult()) .Take(100); We could very easily get a very different, and non-reproducable, set of results, since the ordering of elements in the input collection is not preserved.  To get the same results as our original query, we need to use: IEnumerable<ResultClass> results = collection .AsParallel() .AsOrdered() .Select(e => e.CreateResult()) .Take(100); This requests that PLINQ process our sequence in a way that verifies that our resulting collection is ordered as if it were processed serially.  This will cause our query to run slower, since there is overhead involved in maintaining the ordering.  However, in this case, it is required, since the ordering is required for correctness. PLINQ is incredibly useful.  It allows us to easily take nearly any LINQ to Objects query and run it in parallel, using the same methods and syntax we’ve used previously.  There are some important differences in operation that must be considered, however – it is not a free pass to parallelize everything.  When using PLINQ in order to parallelize your routines declaratively, the same guideline I mentioned before still applies: Parallelization is something that should be handled with care and forethought, added by design, and not just introduced casually.

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  • Working with PivotTables in Excel

    - by Mark Virtue
    PivotTables are one of the most powerful features of Microsoft Excel.  They allow large amounts of data to be analyzed and summarized in just a few mouse clicks. In this article, we explore PivotTables, understand what they are, and learn how to create and customize them. Note:  This article is written using Excel 2010 (Beta).  The concept of a PivotTable has changed little over the years, but the method of creating one has changed in nearly every iteration of Excel.  If you are using a version of Excel that is not 2010, expect different screens from the ones you see in this article. A Little History In the early days of spreadsheet programs, Lotus 1-2-3 ruled the roost.  Its dominance was so complete that people thought it was a waste of time for Microsoft to bother developing their own spreadsheet software (Excel) to compete with Lotus.  Flash-forward to 2010, and Excel’s dominance of the spreadsheet market is greater than Lotus’s ever was, while the number of users still running Lotus 1-2-3 is approaching zero.  How did this happen?  What caused such a dramatic reversal of fortunes? Industry analysts put it down to two factors:  Firstly, Lotus decided that this fancy new GUI platform called “Windows” was a passing fad that would never take off.  They declined to create a Windows version of Lotus 1-2-3 (for a few years, anyway), predicting that their DOS version of the software was all anyone would ever need.  Microsoft, naturally, developed Excel exclusively for Windows.  Secondly, Microsoft developed a feature for Excel that Lotus didn’t provide in 1-2-3, namely PivotTables.  The PivotTables feature, exclusive to Excel, was deemed so staggeringly useful that people were willing to learn an entire new software package (Excel) rather than stick with a program (1-2-3) that didn’t have it.  This one feature, along with the misjudgment of the success of Windows, was the death-knell for Lotus 1-2-3, and the beginning of the success of Microsoft Excel. Understanding PivotTables So what is a PivotTable, exactly? Put simply, a PivotTable is a summary of some data, created to allow easy analysis of said data.  But unlike a manually created summary, Excel PivotTables are interactive.  Once you have created one, you can easily change it if it doesn’t offer the exact insights into your data that you were hoping for.  In a couple of clicks the summary can be “pivoted” – rotated in such a way that the column headings become row headings, and vice versa.  There’s a lot more that can be done, too.  Rather than try to describe all the features of PivotTables, we’ll simply demonstrate them… The data that you analyze using a PivotTable can’t be just any data – it has to be raw data, previously unprocessed (unsummarized) – typically a list of some sort.  An example of this might be the list of sales transactions in a company for the past six months. Examine the data shown below: Notice that this is not raw data.  In fact, it is already a summary of some sort.  In cell B3 we can see $30,000, which apparently is the total of James Cook’s sales for the month of January.  So where is the raw data?  How did we arrive at the figure of $30,000?  Where is the original list of sales transactions that this figure was generated from?  It’s clear that somewhere, someone must have gone to the trouble of collating all of the sales transactions for the past six months into the summary we see above.  How long do you suppose this took?  An hour?  Ten?  Probably. If we were to track down the original list of sales transactions, it might look something like this: You may be surprised to learn that, using the PivotTable feature of Excel, we can create a monthly sales summary similar to the one above in a few seconds, with only a few mouse clicks.  We can do this – and a lot more too! How to Create a PivotTable First, ensure that you have some raw data in a worksheet in Excel.  A list of financial transactions is typical, but it can be a list of just about anything:  Employee contact details, your CD collection, or fuel consumption figures for your company’s fleet of cars. So we start Excel… …and we load such a list… Once we have the list open in Excel, we’re ready to start creating the PivotTable. Click on any one single cell within the list: Then, from the Insert tab, click the PivotTable icon: The Create PivotTable box appears, asking you two questions:  What data should your new PivotTable be based on, and where should it be created?  Because we already clicked on a cell within the list (in the step above), the entire list surrounding that cell is already selected for us ($A$1:$G$88 on the Payments sheet, in this example).  Note that we could select a list in any other region of any other worksheet, or even some external data source, such as an Access database table, or even a MS-SQL Server database table.  We also need to select whether we want our new PivotTable to be created on a new worksheet, or on an existing one.  In this example we will select a new one: The new worksheet is created for us, and a blank PivotTable is created on that worksheet: Another box also appears:  The PivotTable Field List.  This field list will be shown whenever we click on any cell within the PivotTable (above): The list of fields in the top part of the box is actually the collection of column headings from the original raw data worksheet.  The four blank boxes in the lower part of the screen allow us to choose the way we would like our PivotTable to summarize the raw data.  So far, there is nothing in those boxes, so the PivotTable is blank.  All we need to do is drag fields down from the list above and drop them in the lower boxes.  A PivotTable is then automatically created to match our instructions.  If we get it wrong, we only need to drag the fields back to where they came from and/or drag new fields down to replace them. The Values box is arguably the most important of the four.  The field that is dragged into this box represents the data that needs to be summarized in some way (by summing, averaging, finding the maximum, minimum, etc).  It is almost always numerical data.  A perfect candidate for this box in our sample data is the “Amount” field/column.  Let’s drag that field into the Values box: Notice that (a) the “Amount” field in the list of fields is now ticked, and “Sum of Amount” has been added to the Values box, indicating that the amount column has been summed. If we examine the PivotTable itself, we indeed find the sum of all the “Amount” values from the raw data worksheet: We’ve created our first PivotTable!  Handy, but not particularly impressive.  It’s likely that we need a little more insight into our data than that. Referring to our sample data, we need to identify one or more column headings that we could conceivably use to split this total.  For example, we may decide that we would like to see a summary of our data where we have a row heading for each of the different salespersons in our company, and a total for each.  To achieve this, all we need to do is to drag the “Salesperson” field into the Row Labels box: Now, finally, things start to get interesting!  Our PivotTable starts to take shape….   With a couple of clicks we have created a table that would have taken a long time to do manually. So what else can we do?  Well, in one sense our PivotTable is complete.  We’ve created a useful summary of our source data.  The important stuff is already learned!  For the rest of the article, we will examine some ways that more complex PivotTables can be created, and ways that those PivotTables can be customized. First, we can create a two-dimensional table.  Let’s do that by using “Payment Method” as a column heading.  Simply drag the “Payment Method” heading to the Column Labels box: Which looks like this: Starting to get very cool! Let’s make it a three-dimensional table.  What could such a table possibly look like?  Well, let’s see… Drag the “Package” column/heading to the Report Filter box: Notice where it ends up…. This allows us to filter our report based on which “holiday package” was being purchased.  For example, we can see the breakdown of salesperson vs payment method for all packages, or, with a couple of clicks, change it to show the same breakdown for the “Sunseekers” package: And so, if you think about it the right way, our PivotTable is now three-dimensional.  Let’s keep customizing… If it turns out, say, that we only want to see cheque and credit card transactions (i.e. no cash transactions), then we can deselect the “Cash” item from the column headings.  Click the drop-down arrow next to Column Labels, and untick “Cash”: Let’s see what that looks like…As you can see, “Cash” is gone. Formatting This is obviously a very powerful system, but so far the results look very plain and boring.  For a start, the numbers that we’re summing do not look like dollar amounts – just plain old numbers.  Let’s rectify that. A temptation might be to do what we’re used to doing in such circumstances and simply select the whole table (or the whole worksheet) and use the standard number formatting buttons on the toolbar to complete the formatting.  The problem with that approach is that if you ever change the structure of the PivotTable in the future (which is 99% likely), then those number formats will be lost.  We need a way that will make them (semi-)permanent. First, we locate the “Sum of Amount” entry in the Values box, and click on it.  A menu appears.  We select Value Field Settings… from the menu: The Value Field Settings box appears. Click the Number Format button, and the standard Format Cells box appears: From the Category list, select (say) Accounting, and drop the number of decimal places to 0.  Click OK a few times to get back to the PivotTable… As you can see, the numbers have been correctly formatted as dollar amounts. While we’re on the subject of formatting, let’s format the entire PivotTable.  There are a few ways to do this.  Let’s use a simple one… Click the PivotTable Tools/Design tab: Then drop down the arrow in the bottom-right of the PivotTable Styles list to see a vast collection of built-in styles: Choose any one that appeals, and look at the result in your PivotTable:   Other Options We can work with dates as well.  Now usually, there are many, many dates in a transaction list such as the one we started with.  But Excel provides the option to group data items together by day, week, month, year, etc.  Let’s see how this is done. First, let’s remove the “Payment Method” column from the Column Labels box (simply drag it back up to the field list), and replace it with the “Date Booked” column: As you can see, this makes our PivotTable instantly useless, giving us one column for each date that a transaction occurred on – a very wide table! To fix this, right-click on any date and select Group… from the context-menu: The grouping box appears.  We select Months and click OK: Voila!  A much more useful table: (Incidentally, this table is virtually identical to the one shown at the beginning of this article – the original sales summary that was created manually.) Another cool thing to be aware of is that you can have more than one set of row headings (or column headings): …which looks like this…. You can do a similar thing with column headings (or even report filters). Keeping things simple again, let’s see how to plot averaged values, rather than summed values. First, click on “Sum of Amount”, and select Value Field Settings… from the context-menu that appears: In the Summarize value field by list in the Value Field Settings box, select Average: While we’re here, let’s change the Custom Name, from “Average of Amount” to something a little more concise.  Type in something like “Avg”: Click OK, and see what it looks like.  Notice that all the values change from summed totals to averages, and the table title (top-left cell) has changed to “Avg”: If we like, we can even have sums, averages and counts (counts = how many sales there were) all on the same PivotTable! Here are the steps to get something like that in place (starting from a blank PivotTable): Drag “Salesperson” into the Column Labels Drag “Amount” field down into the Values box three times For the first “Amount” field, change its custom name to “Total” and it’s number format to Accounting (0 decimal places) For the second “Amount” field, change its custom name to “Average”, its function to Average and it’s number format to Accounting (0 decimal places) For the third “Amount” field, change its name to “Count” and its function to Count Drag the automatically created field from Column Labels to Row Labels Here’s what we end up with: Total, average and count on the same PivotTable! Conclusion There are many, many more features and options for PivotTables created by Microsoft Excel – far too many to list in an article like this.  To fully cover the potential of PivotTables, a small book (or a large website) would be required.  Brave and/or geeky readers can explore PivotTables further quite easily:  Simply right-click on just about everything, and see what options become available to you.  There are also the two ribbon-tabs: PivotTable Tools/Options and Design.  It doesn’t matter if you make a mistake – it’s easy to delete the PivotTable and start again – a possibility old DOS users of Lotus 1-2-3 never had. We’ve included an Excel that should work with most versions of Excel, so you can download to practice your PivotTable skills. Download Our Practice Excel File Similar Articles Productive Geek Tips Magnify Selected Cells In Excel 2007Share Access Data with Excel in Office 2010Make Excel 2007 Print Gridlines In Workbook FileMake Excel 2007 Always Save in Excel 2003 FormatConvert Older Excel Documents to Excel 2007 Format TouchFreeze Alternative in AutoHotkey The Icy Undertow Desktop Windows Home Server – Backup to LAN The Clear & Clean Desktop Use This Bookmarklet to Easily Get Albums Use AutoHotkey to Assign a Hotkey to a Specific Window Latest Software Reviews Tinyhacker Random Tips Revo Uninstaller Pro Registry Mechanic 9 for Windows PC Tools Internet Security Suite 2010 PCmover Professional Ben & Jerry’s Free Cone Day, 3/23/10 New Stinger from McAfee Helps Remove ‘FakeAlert’ Threats Google Apps Marketplace: Tools & Services For Google Apps Users Get News Quick and Precise With Newser Scan for Viruses in Ubuntu using ClamAV Replace Your Windows Task Manager With System Explorer

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  • Setting up a new Silverlight 4 Project with WCF RIA Services

    - by Kevin Grossnicklaus
    Many of my clients are actively using Silverlight 4 and RIA Services to build powerful line of business applications.  Getting things set up correctly is critical to being to being able to take full advantage of the RIA services plumbing and when developers struggle with the setup they tend to shy away from the solution as a whole.  I’m a big proponent of RIA services and wanted to take the opportunity to share some of my experiences in setting up these types of projects.  In late 2010 I presented a RIA Services Master Class here in St. Louis, MO through my firm (ArchitectNow) and the information shared in this post was promised during that presentation. One other thing I want to mention before diving in is the existence of a number of other great posts on this subject.  I’ve learned a lot from many of them and wanted to call out a few of them.  The purpose of my post is to point out some of the gotchas that people get caught up on in the process but I would still encourage you to do as much additional research as you can to find the perfect setup for your needs. Here are a few additional blog posts and articles you should check out on the subject: http://msdn.microsoft.com/en-us/library/ee707351(VS.91).aspx http://adam-thompson.com/post/2010/07/03/Getting-Started-with-WCF-RIA-Services-for-Silverlight-4.aspx Technologies I don’t intend for this post to turn into a full WCF RIA Services tutorial but I did want to point out what technologies we will be using: Visual Studio.NET 2010 Silverlight 4.0 WCF RIA Services for Visual Studio 2010 Entity Framework 4.0 I also wanted to point out that the screenshots came from my personal development box which has a number of additional plug-ins and frameworks loaded so a few of the screenshots might not match 100% with what you see on your own machines. If you do not have Visual Studio 2010 you can download the express version from http://www.microsoft.com/express.  The Silverlight 4.0 tools and the WCF RIA Services components are installed via the Web Platform Installer (http://www.microsoft.com/web/download). Also, the examples given in this post are done in C#…sorry to you VB folks but the concepts are 100% identical. Setting up anew RIA Services Project This section will provide a step-by-step walkthrough of setting up a new RIA services project using a shared DLL for server side code and a simple Entity Framework model for data access.  All projects are created with the consistent ArchitectNow.RIAServices filename prefix and default namespace.  This would be modified to match your companies standards. First, open Visual Studio and open the new project window via File->New->Project.  In the New Project window, select the Silverlight folder in the Installed Templates section on the left and select “Silverlight Application” as your project type.  Verify your solution name and location are set appropriately.  Note that the project name we specified in the example below ends with .Client.  This indicates the name which will be given to our Silverlight project. I consider Silverlight a client-side technology and thus use this name to reflect that.  Click Ok to continue. During the creation on a new Silverlight 4 project you will be prompted with the following dialog to create a new web ASP.NET web project to host your Silverlight content.  As we are demonstrating the setup of a WCF RIA Services infrastructure, make sure the “Enable WCF RIA Services” option is checked and click OK.  Obviously, there are some other options here which have an effect on your solution and you are welcome to look around.  For our example we are going to leave the ASP.NET Web Application Project selected.  If you are interested in having your Silverlight project hosted in an MVC 2 application or a Web Site project these options are available as well.  Also, whichever web project type you select, the name can be modified here as well.  Note that it defaults to the same name as your Silverlight project with the addition of a .Web suffix. At this point, your full Silverlight 4 project and host ASP.NET Web Application should be created and will now display in your Visual Studio solution explorer as part of a single Visual Studio solution as follows: Now we want to add our WCF RIA Services projects to this same solution.  To do so, right-click on the Solution node in the solution explorer and select Add->New Project.  In the New Project dialog again select the Silverlight folder under the Visual C# node on the left and, in the main area of the screen, select the WCF RIA Services Class Library project template as shown below.  Make sure your project name is set appropriately as well.  For the sample below, we will name the project “ArchitectNow.RIAServices.Server.Entities”.   The .Server.Entities suffix we use is meant to simply indicate that this particular project will contain our WCF RIA Services entity classes (as you will see below).  Click OK to continue. Once you have created the WCF RIA Services Class Library specified above, Visual Studio will automatically add TWO projects to your solution.  The first will be an project called .Server.Entities (using our naming conventions) and the other will have the same name with a .Web extension.  The full solution (with all 4 projects) is shown in the image below.  The .Entities project will essentially remain empty and is actually a Silverlight 4 class library that will contain generated RIA Services domain objects.  It will be referenced by our front-end Silverlight project and thus allow for simplified sharing of code between the client and the server.   The .Entities.Web project is a .NET 4.0 class library into which we will put our data access code (via Entity Framework).  This is our server side code and business logic and the RIA Services plumbing will maintain a link between this project and the front end.  Specific entities such as our domain objects and other code we set to be shared will be copied automatically into the .Entities project to be used in both the front end and the back end. At this point, we want to do a little cleanup of the projects in our solution and we will do so by deleting the “Class1.cs” class from both the .Entities project and the .Entities.Web project.  (Has anyone ever intentionally named a class “Class1”?) Next, we need to configure a few references to make RIA Services work.  THIS IS A KEY STEP THAT CAUSES MANY HEADACHES FOR DEVELOPERS NEW TO THIS INFRASTRUCTURE! Using the Add References dialog in Visual Studio, add a project reference from the *.Client project (our Silverlight 4 client) to the *.Entities project (our RIA Services class library).  Next, again using the Add References dialog in Visual Studio, add a project reference from the *.Client.Web project (our ASP.NET host project) to the *.Entities.Web project (our back-end data services DLL).  To get to the Add References dialog, simply right-click on the project you with to add a reference to in the Visual Studio solution explorer and select “Add Reference” from the resulting context menu.  You will want to make sure these references are added as “Project” references to simplify your future debugging.  To reiterate the reference direction using the project names we have utilized in this example thus far:  .Client references .Entities and .Client.Web reference .Entities.Web.  If you have opted for a different naming convention, then the Silverlight project must reference the RIA Services Silverlight class library and the ASP.NET host project must reference the server-side class library. Next, we are going to add a new Entity Framework data model to our data services project (.Entities.Web).  We will do this by right clicking on this project (ArchitectNow.Server.Entities.Web in the above diagram) and selecting Add->New Project.  In the New Project dialog we will select ADO.NET Entity Data Model as in the following diagram.  For now we will call this simply SampleDataModel.edmx and click OK. It is worth pointing out that WCF RIA Services is in no way tied to the Entity Framework as a means of accessing data and any data access technology is supported (as long as the server side implementation maps to the RIA Services pattern which is a topic beyond the scope of this post).  We are using EF to quickly demonstrate the RIA Services concepts and setup infrastructure, as such, I am not providing a database schema with this post but am instead connecting to a small sample database on my local machine.  The following diagram shows a simple EF Data Model with two tables that I reverse engineered from a local data store.   If you are putting together your own solution, feel free to reverse engineer a few tables from any local database to which you have access. At this point, once you have an EF data model generated as an EDMX into your .Entites.Web project YOU MUST BUILD YOUR SOLUTION.  I know it seems strange to call that out but it important that the solution be built at this point for the next step to be successful.  Obviously, if you have any build errors, these must be addressed at this point. At this point we will add a RIA Services Domain Service to our .Entities.Web project (our server side code).  We will need to right-click on the .Entities.Web project and select Add->New Item.  In the Add New Item dialog, select Domain Service Class and verify the name of your new Domain Service is correct (ours is called SampleService.cs in the image below).  Next, click "Add”. After clicking “Add” to include the Domain Service Class in the selected project, you will be presented with the following dialog.  In it, you can choose which entities from the selected EDMX to include in your services and if they should be allowed to be edited (i.e. inserted, updated, or deleted) via this service.  If the “Available DataContext/ObjectContext classes” dropdown is empty, this indicates you have not yes successfully built your project after adding your EDMX.  I would also recommend verifying that the “Generate associated classes for metadata” option is selected.  Once you have selected the appropriate options, click “OK”. Once you have added the domain service class to the .Entities.Web project, the resulting solution should look similar to the following: Note that in the solution you now have a SampleDataModel.edmx which represents your EF data mapping to your database and a SampleService.cs which will contain a large amount of generated RIA Services code which RIA Services utilizes to access this data from the Silverlight front-end.  You will put all your server side data access code and logic into the SampleService.cs class.  The SampleService.metadata.cs class is for decorating the generated domain objects with attributes from the System.ComponentModel.DataAnnotations namespace for validation purposes. FINAL AND KEY CONFIGURATION STEP!  One key step that causes significant headache to developers configuring RIA Services for the first time is the fact that, when we added the EDMX to the .Entities.Web project for our EF data access, a connection string was generated and placed within a newly generated App.Context file within that project.  While we didn’t point it out at the time you can see it in the image above.  This connection string will be required for the EF data model to successfully locate it’s data.  Also, when we added the Domain Service class to the .Entities.Web project, a number of RIA Services configuration options were added to the same App.Config file.   Unfortunately, when we ultimately begin to utilize the RIA Services infrastructure, our Silverlight UI will be making RIA services calls through the ASP.NET host project (i.e. .Client.Web).  This host project has a reference to the .Entities.Web project which actually contains the code so all will pass through correctly EXCEPT the fact that the host project will utilize it’s own Web.Config for any configuration settings.  For this reason we must now merge all the sections of the App.Config file in the .Entities.Web project into the Web.Config file in the .Client.Web project.  I know this is a bit tedious and I wish there were a simpler solution but it is required for our RIA Services Domain Service to be made available to the front end Silverlight project.  Much of this manual merge can be achieved by simply cutting and pasting from App.Config into Web.Config.  Unfortunately, the <system.webServer> section will exist in both and the contents of this section will need to be manually merged.  Fortunately, this is a step that needs to be taken only once per solution.  As you add additional data structures and Domain Services methods to the server no additional changes will be necessary to the Web.Config. Next Steps At this point, we have walked through the basic setup of a simple RIA services solution.  Unfortunately, there is still a lot to know about RIA services and we have not even begun to take advantage of the plumbing which we just configured (meaning we haven’t even made a single RIA services call).  I plan on posting a few more introductory posts over the next few weeks to take us to this step.  If you have any questions on the content in this post feel free to reach out to me via this Blog and I’ll gladly point you in (hopefully) the right direction. Resources Prior to closing out this post, I wanted to share a number or resources to help you get started with RIA services.  While I plan on posting more on the subject, I didn’t invent any of this stuff and wanted to give credit to the following areas for helping me put a lot of these pieces into place.   The books and online resources below will go a long way to making you extremely productive with RIA services in the shortest time possible.  The only thing required of you is the dedication to take advantage of the resources available. Books Pro Business Applications with Silverlight 4 http://www.amazon.com/Pro-Business-Applications-Silverlight-4/dp/1430272074/ref=sr_1_2?ie=UTF8&qid=1291048751&sr=8-2 Silverlight 4 in Action http://www.amazon.com/Silverlight-4-Action-Pete-Brown/dp/1935182374/ref=sr_1_1?ie=UTF8&qid=1291048751&sr=8-1 Pro Silverlight for the Enterprise (Books for Professionals by Professionals) http://www.amazon.com/Pro-Silverlight-Enterprise-Books-Professionals/dp/1430218673/ref=sr_1_3?ie=UTF8&qid=1291048751&sr=8-3 Web Content RIA Services http://channel9.msdn.com/Blogs/RobBagby/NET-RIA-Services-in-5-Minutes http://silverlight.net/riaservices/ http://www.silverlight.net/learn/videos/all/net-ria-services-intro/ http://www.silverlight.net/learn/videos/all/ria-services-support-visual-studio-2010/ http://channel9.msdn.com/learn/courses/Silverlight4/SL4BusinessModule2/SL4LOB_02_01_RIAServices http://www.myvbprof.com/MainSite/index.aspx#/zSL4_RIA_01 http://channel9.msdn.com/blogs/egibson/silverlight-firestarter-ria-services http://msdn.microsoft.com/en-us/library/ee707336%28v=VS.91%29.aspx Silverlight www.silverlight.net http://msdn.microsoft.com/en-us/silverlight4trainingcourse.aspx http://channel9.msdn.com/shows/silverlighttv

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  • Recover Data Like a Forensics Expert Using an Ubuntu Live CD

    - by Trevor Bekolay
    There are lots of utilities to recover deleted files, but what if you can’t boot up your computer, or the whole drive has been formatted? We’ll show you some tools that will dig deep and recover the most elusive deleted files, or even whole hard drive partitions. We’ve shown you simple ways to recover accidentally deleted files, even a simple method that can be done from an Ubuntu Live CD, but for hard disks that have been heavily corrupted, those methods aren’t going to cut it. In this article, we’ll examine four tools that can recover data from the most messed up hard drives, regardless of whether they were formatted for a Windows, Linux, or Mac computer, or even if the partition table is wiped out entirely. Note: These tools cannot recover data that has been overwritten on a hard disk. Whether a deleted file has been overwritten depends on many factors – the quicker you realize that you want to recover a file, the more likely you will be able to do so. Our setup To show these tools, we’ve set up a small 1 GB hard drive, with half of the space partitioned as ext2, a file system used in Linux, and half the space partitioned as FAT32, a file system used in older Windows systems. We stored ten random pictures on each hard drive. We then wiped the partition table from the hard drive by deleting the partitions in GParted. Is our data lost forever? Installing the tools All of the tools we’re going to use are in Ubuntu’s universe repository. To enable the repository, open Synaptic Package Manager by clicking on System in the top-left, then Administration > Synaptic Package Manager. Click on Settings > Repositories and add a check in the box labelled “Community-maintained Open Source software (universe)”. Click Close, and then in the main Synaptic Package Manager window, click the Reload button. Once the package list has reloaded, and the search index rebuilt, search for and mark for installation one or all of the following packages: testdisk, foremost, and scalpel. Testdisk includes TestDisk, which can recover lost partitions and repair boot sectors, and PhotoRec, which can recover many different types of files from tons of different file systems. Foremost, originally developed by the US Air Force Office of Special Investigations, recovers files based on their headers and other internal structures. Foremost operates on hard drives or drive image files generated by various tools. Finally, scalpel performs the same functions as foremost, but is focused on enhanced performance and lower memory usage. Scalpel may run better if you have an older machine with less RAM. Recover hard drive partitions If you can’t mount your hard drive, then its partition table might be corrupted. Before you start trying to recover your important files, it may be possible to recover one or more partitions on your drive, recovering all of your files with one step. Testdisk is the tool for the job. Start it by opening a terminal (Applications > Accessories > Terminal) and typing in: sudo testdisk If you’d like, you can create a log file, though it won’t affect how much data you recover. Once you make your choice, you’re greeted with a list of the storage media on your machine. You should be able to identify the hard drive you want to recover partitions from by its size and label. TestDisk asks you select the type of partition table to search for. In most cases (ext2/3, NTFS, FAT32, etc.) you should select Intel and press Enter. Highlight Analyse and press enter. In our case, our small hard drive has previously been formatted as NTFS. Amazingly, TestDisk finds this partition, though it is unable to recover it. It also finds the two partitions we just deleted. We are able to change their attributes, or add more partitions, but we’ll just recover them by pressing Enter. If TestDisk hasn’t found all of your partitions, you can try doing a deeper search by selecting that option with the left and right arrow keys. We only had these two partitions, so we’ll recover them by selecting Write and pressing Enter. Testdisk informs us that we will have to reboot. Note: If your Ubuntu Live CD is not persistent, then when you reboot you will have to reinstall any tools that you installed earlier. After restarting, both of our partitions are back to their original states, pictures and all. Recover files of certain types For the following examples, we deleted the 10 pictures from both partitions and then reformatted them. PhotoRec Of the three tools we’ll show, PhotoRec is the most user-friendly, despite being a console-based utility. To start recovering files, open a terminal (Applications > Accessories > Terminal) and type in: sudo photorec To begin, you are asked to select a storage device to search. You should be able to identify the right device by its size and label. Select the right device, and then hit Enter. PhotoRec asks you select the type of partition to search. In most cases (ext2/3, NTFS, FAT, etc.) you should select Intel and press Enter. You are given a list of the partitions on your selected hard drive. If you want to recover all of the files on a partition, then select Search and hit enter. However, this process can be very slow, and in our case we only want to search for pictures files, so instead we use the right arrow key to select File Opt and press Enter. PhotoRec can recover many different types of files, and deselecting each one would take a long time. Instead, we press “s” to clear all of the selections, and then find the appropriate file types – jpg, gif, and png – and select them by pressing the right arrow key. Once we’ve selected these three, we press “b” to save these selections. Press enter to return to the list of hard drive partitions. We want to search both of our partitions, so we highlight “No partition” and “Search” and then press Enter. PhotoRec prompts for a location to store the recovered files. If you have a different healthy hard drive, then we recommend storing the recovered files there. Since we’re not recovering very much, we’ll store it on the Ubuntu Live CD’s desktop. Note: Do not recover files to the hard drive you’re recovering from. PhotoRec is able to recover the 20 pictures from the partitions on our hard drive! A quick look in the recup_dir.1 directory that it creates confirms that PhotoRec has recovered all of our pictures, save for the file names. Foremost Foremost is a command-line program with no interactive interface like PhotoRec, but offers a number of command-line options to get as much data out of your had drive as possible. For a full list of options that can be tweaked via the command line, open up a terminal (Applications > Accessories > Terminal) and type in: foremost –h In our case, the command line options that we are going to use are: -t, a comma-separated list of types of files to search for. In our case, this is “jpeg,png,gif”. -v, enabling verbose-mode, giving us more information about what foremost is doing. -o, the output folder to store recovered files in. In our case, we created a directory called “foremost” on the desktop. -i, the input that will be searched for files. This can be a disk image in several different formats; however, we will use a hard disk, /dev/sda. Our foremost invocation is: sudo foremost –t jpeg,png,gif –o foremost –v –i /dev/sda Your invocation will differ depending on what you’re searching for and where you’re searching for it. Foremost is able to recover 17 of the 20 files stored on the hard drive. Looking at the files, we can confirm that these files were recovered relatively well, though we can see some errors in the thumbnail for 00622449.jpg. Part of this may be due to the ext2 filesystem. Foremost recommends using the –d command-line option for Linux file systems like ext2. We’ll run foremost again, adding the –d command-line option to our foremost invocation: sudo foremost –t jpeg,png,gif –d –o foremost –v –i /dev/sda This time, foremost is able to recover all 20 images! A final look at the pictures reveals that the pictures were recovered with no problems. Scalpel Scalpel is another powerful program that, like Foremost, is heavily configurable. Unlike Foremost, Scalpel requires you to edit a configuration file before attempting any data recovery. Any text editor will do, but we’ll use gedit to change the configuration file. In a terminal window (Applications > Accessories > Terminal), type in: sudo gedit /etc/scalpel/scalpel.conf scalpel.conf contains information about a number of different file types. Scroll through this file and uncomment lines that start with a file type that you want to recover (i.e. remove the “#” character at the start of those lines). Save the file and close it. Return to the terminal window. Scalpel also has a ton of command-line options that can help you search quickly and effectively; however, we’ll just define the input device (/dev/sda) and the output folder (a folder called “scalpel” that we created on the desktop). Our invocation is: sudo scalpel /dev/sda –o scalpel Scalpel is able to recover 18 of our 20 files. A quick look at the files scalpel recovered reveals that most of our files were recovered successfully, though there were some problems (e.g. 00000012.jpg). Conclusion In our quick toy example, TestDisk was able to recover two deleted partitions, and PhotoRec and Foremost were able to recover all 20 deleted images. Scalpel recovered most of the files, but it’s very likely that playing with the command-line options for scalpel would have enabled us to recover all 20 images. These tools are lifesavers when something goes wrong with your hard drive. If your data is on the hard drive somewhere, then one of these tools will track it down! Similar Articles Productive Geek Tips Recover Deleted Files on an NTFS Hard Drive from a Ubuntu Live CDUse an Ubuntu Live CD to Securely Wipe Your PC’s Hard DriveReset Your Ubuntu Password Easily from the Live CDBackup Your Windows Live Writer SettingsAdding extra Repositories on Ubuntu TouchFreeze Alternative in AutoHotkey The Icy Undertow Desktop Windows Home Server – Backup to LAN The Clear & Clean Desktop Use This Bookmarklet to Easily Get Albums Use AutoHotkey to Assign a Hotkey to a Specific Window Latest Software Reviews Tinyhacker Random Tips DVDFab 6 Revo Uninstaller Pro Registry Mechanic 9 for Windows PC Tools Internet Security Suite 2010 Awe inspiring, inter-galactic theme (Win 7) Case Study – How to Optimize Popular Wordpress Sites Restore Hidden Updates in Windows 7 & Vista Iceland an Insurance Job? Find Downloads and Add-ins for Outlook Recycle !

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  • Using Oracle Proxy Authentication with JPA (eclipselink-Style)

    - by olaf.heimburger
    Security is a very intriguing topic. You will find it everywhere and you need to implement it everywhere. Yes, you need. Unfortunately, one can easily forget it while implementing the last mile. The Last Mile In a multi-tier application it is a common practice to use connection pools between the business layer and the database layer. Connection pools are quite useful to speed database connection creation and to split the load. Another very common practice is to use a specific, often called technical, user to connect to the database. This user has authentication and authorization rules that apply to all application users. Imagine you've put every effort to define roles for different types of users that use your application. These roles are necessary to differentiate between normal users, premium users, and administrators (I bet you will find or already have more roles in your application). While these user roles are pretty well used within your application, once the flow of execution enters the database everything is gone. Each and every user just has one role and is the same database user. Issues? What Issues? As long as things go well, this is not a real issue. However, things do not go well all the time. Once your application becomes famous performance decreases in certain situations or, more importantly, current and upcoming regulations and laws require that your application must be able to apply different security measures on a per user role basis at every stage of your application. If you only have a bunch of users with the same name and role you are not able to find the application usage profile that causes the performance issue, or which user has accessed data that he/she is not allowed to. Another thread to your role concept is that databases tend to be used by different applications and tools. These tools can be developer tools like SQL*Plus, SQL Developer, etc. or end user applications like BI Publisher, Oracle Forms and so on. These tools have no idea of your applications role concept and access the database the way they think is appropriate. A big oversight for your perfect role model and a big nightmare for your Chief Security Officer. Speaking of the CSO, brings up another issue: Password management. Once your technical user account is compromised, every user is able to do things that he/she is not expected to do from the design of your application. Counter Measures In the Oracle world a common counter measure is to use Virtual Private Database (VPD). This restricts the values a database user can see to the allowed minimum. However, it doesn't help in regard of a connection pool user, because this one is still not the real user. Oracle Proxy Authentication Another feature of the Oracle database is Proxy Authentication. First introduced with version 9i it is a quite useful feature for nearly every situation. The main idea behind Proxy Authentication is, to create a crippled database user who has only connect rights. Even if this user is compromised the risks are well understood and fairly limited. This user can be used in every situation in which you need to connect to the database, no matter which tool or application (see above) you use.The proxy user is perfect for multi-tier connection pools. CREATE USER app_user IDENTIFIED BY abcd1234; GRANT CREATE SESSION TO app_user; But what if you need to access real data? Well, this is the primary use case, isn't it? Now is the time to bring the application's role concept into play. You define database roles that define the grants for your identified user groups. Once you have these groups you grant access through the proxy user with the application role to the specific user. CREATE ROLE app_role_a; GRANT app_role_a TO scott; ALTER USER scott GRANT CONNECT THROUGH app_user WITH ROLE app_role_a; Now, hr has permission to connect to the database through the proxy user. Through the role you can restrict the hr's rights the are needed for the application only. If hr connects to the database directly all assigned role and permissions apply. Testing the Setup To test the setup you can use SQL*Plus and connect to your database: $ sqlplus app_user[hr]/abcd1234 Java Persistence API The Java Persistence API (JPA) is a fairly easy means to build applications that retrieve data from the database and put it into Java objects. You use plain old Java objects (POJOs) and mixin some Java annotations that define how the attributes of the object are used for storing data from the database into the Java object. Here is a sample for objects from the HR sample schema EMPLOYEES table. When using Java annotations you only specify what can not be deduced from the code. If your Java class name is Employee but the table name is EMPLOYEES, you need to specify the table name, otherwise it will fail. package demo.proxy.ejb; import java.io.Serializable; import java.sql.Timestamp; import java.util.List; import javax.persistence.Column; import javax.persistence.Entity; import javax.persistence.Id; import javax.persistence.JoinColumn; import javax.persistence.ManyToOne; import javax.persistence.NamedQueries; import javax.persistence.NamedQuery; import javax.persistence.OneToMany; import javax.persistence.Table; @Entity @NamedQueries({ @NamedQuery(name = "Employee.findAll", query = "select o from Employee o") }) @Table(name = "EMPLOYEES") public class Employee implements Serializable { @Column(name="COMMISSION_PCT") private Double commissionPct; @Column(name="DEPARTMENT_ID") private Long departmentId; @Column(nullable = false, unique = true, length = 25) private String email; @Id @Column(name="EMPLOYEE_ID", nullable = false) private Long employeeId; @Column(name="FIRST_NAME", length = 20) private String firstName; @Column(name="HIRE_DATE", nullable = false) private Timestamp hireDate; @Column(name="JOB_ID", nullable = false, length = 10) private String jobId; @Column(name="LAST_NAME", nullable = false, length = 25) private String lastName; @Column(name="PHONE_NUMBER", length = 20) private String phoneNumber; private Double salary; @ManyToOne @JoinColumn(name = "MANAGER_ID") private Employee employee; @OneToMany(mappedBy = "employee") private List employeeList; public Employee() { } public Employee(Double commissionPct, Long departmentId, String email, Long employeeId, String firstName, Timestamp hireDate, String jobId, String lastName, Employee employee, String phoneNumber, Double salary) { this.commissionPct = commissionPct; this.departmentId = departmentId; this.email = email; this.employeeId = employeeId; this.firstName = firstName; this.hireDate = hireDate; this.jobId = jobId; this.lastName = lastName; this.employee = employee; this.phoneNumber = phoneNumber; this.salary = salary; } public Double getCommissionPct() { return commissionPct; } public void setCommissionPct(Double commissionPct) { this.commissionPct = commissionPct; } public Long getDepartmentId() { return departmentId; } public void setDepartmentId(Long departmentId) { this.departmentId = departmentId; } public String getEmail() { return email; } public void setEmail(String email) { this.email = email; } public Long getEmployeeId() { return employeeId; } public void setEmployeeId(Long employeeId) { this.employeeId = employeeId; } public String getFirstName() { return firstName; } public void setFirstName(String firstName) { this.firstName = firstName; } public Timestamp getHireDate() { return hireDate; } public void setHireDate(Timestamp hireDate) { this.hireDate = hireDate; } public String getJobId() { return jobId; } public void setJobId(String jobId) { this.jobId = jobId; } public String getLastName() { return lastName; } public void setLastName(String lastName) { this.lastName = lastName; } public String getPhoneNumber() { return phoneNumber; } public void setPhoneNumber(String phoneNumber) { this.phoneNumber = phoneNumber; } public Double getSalary() { return salary; } public void setSalary(Double salary) { this.salary = salary; } public Employee getEmployee() { return employee; } public void setEmployee(Employee employee) { this.employee = employee; } public List getEmployeeList() { return employeeList; } public void setEmployeeList(List employeeList) { this.employeeList = employeeList; } public Employee addEmployee(Employee employee) { getEmployeeList().add(employee); employee.setEmployee(this); return employee; } public Employee removeEmployee(Employee employee) { getEmployeeList().remove(employee); employee.setEmployee(null); return employee; } } JPA could be used in standalone applications and Java EE containers. In both worlds you normally create a Facade to retrieve or store the values of the Entities to or from the database. The Facade does this via an EntityManager which will be injected by the Java EE container. Here is sample Facade Session Bean for a Java EE container. package demo.proxy.ejb; import java.util.HashMap; import java.util.List; import javax.ejb.Local; import javax.ejb.Remote; import javax.ejb.Stateless; import javax.persistence.EntityManager; import javax.persistence.PersistenceContext; import javax.persistence.Query; import javax.interceptor.AroundInvoke; import javax.interceptor.InvocationContext; import oracle.jdbc.driver.OracleConnection; import org.eclipse.persistence.config.EntityManagerProperties; import org.eclipse.persistence.internal.jpa.EntityManagerImpl; @Stateless(name = "DataFacade", mappedName = "ProxyUser-TestEJB-DataFacade") @Remote @Local public class DataFacadeBean implements DataFacade, DataFacadeLocal { @PersistenceContext(unitName = "TestEJB") private EntityManager em; private String username; public Object queryByRange(String jpqlStmt, int firstResult, int maxResults) { // setSessionUser(); Query query = em.createQuery(jpqlStmt); if (firstResult 0) { query = query.setFirstResult(firstResult); } if (maxResults 0) { query = query.setMaxResults(maxResults); } return query.getResultList(); } public Employee persistEmployee(Employee employee) { // setSessionUser(); em.persist(employee); return employee; } public Employee mergeEmployee(Employee employee) { // setSessionUser(); return em.merge(employee); } public void removeEmployee(Employee employee) { // setSessionUser(); employee = em.find(Employee.class, employee.getEmployeeId()); em.remove(employee); } /** select o from Employee o */ public List getEmployeeFindAll() { Query q = em.createNamedQuery("Employee.findAll"); return q.getResultList(); } Putting Both Together To use Proxy Authentication with JPA and within a Java EE container you have to take care of the additional requirements: Use an OCI JDBC driver Provide the user name that connects through the proxy user Use an OCI JDBC driver To use the OCI JDBC driver you need to set up your JDBC data source file to use the correct JDBC URL. hr jdbc:oracle:oci8:@(DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=localhost)(PORT=1521))(CONNECT_DATA=(SID=XE))) oracle.jdbc.OracleDriver user app_user 62C32F70E98297522AD97E15439FAC0E SQL SELECT 1 FROM DUAL jdbc/hrDS Application Additionally you need to make sure that the version of the shared libraries of the OCI driver match the version of the JDBC driver in your Java EE container or Java application and are within your PATH (on Windows) or LD_LIBRARY_PATH (on most Unix-based systems). Installing the Oracle Database Instance Client software works perfectly. Provide the user name that connects through the proxy user This part needs some modification of your application software and session facade. Session Facade Changes In the Session Facade we must ensure that every call that goes through the EntityManager must be prepared correctly and uniquely assigned to this session. The second is really important, as the EntityManager works with a connection pool and can not guarantee that we set the proxy user on the connection that will be used for the database activities. To avoid changing every method call of the Session Facade we provide a method to set the username of the user that connects through the proxy user. This method needs to be called by the Facade client bfore doing anything else. public void setUsername(String name) { username = name; } Next we provide a means to instruct the TopLink EntityManager Delegate to use Oracle Proxy Authentication. (I love small helper methods to hide the nitty-gritty details and avoid repeating myself.) private void setSessionUser() { setSessionUser(username); } private void setSessionUser(String user) { if (user != null && !user.isEmpty()) { EntityManagerImpl emDelegate = ((EntityManagerImpl)em.getDelegate()); emDelegate.setProperty(EntityManagerProperties.ORACLE_PROXY_TYPE, OracleConnection.PROXYTYPE_USER_NAME); emDelegate.setProperty(OracleConnection.PROXY_USER_NAME, user); emDelegate.setProperty(EntityManagerProperties.EXCLUSIVE_CONNECTION_MODE, "Always"); } } The final step is use the EJB 3.0 AroundInvoke interceptor. This interceptor will be called around every method invocation. We therefore check whether the Facade methods will be called or not. If so, we set the user for proxy authentication and the normal method flow continues. @AroundInvoke public Object proxyInterceptor(InvocationContext invocationCtx) throws Exception { if (invocationCtx.getTarget() instanceof DataFacadeBean) { setSessionUser(); } return invocationCtx.proceed(); } Benefits Using Oracle Proxy Authentification has a number of additional benefits appart from implementing the role model of your application: Fine grained access control for temporary users of the account, without compromising the original password. Enabling database auditing and logging. Better identification of performance bottlenecks. References Effective Oracle Database 10g Security by Design, David Knox TopLink Developer's Guide, Chapter 98

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