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  • How to pass a Lambda Expression as method parameter with EF

    - by Registered User
    How do I pass an EF expression as a method argument? To illustrate my question I have created a pseudo code example: The first example is my method today. The example utilizes EF and a Fancy Retry Logic. What I need to do is to encapsulate the Fancy Retry Logic so that it becomes more generic and does not duplicate. In the second example is how I want it to be, with a helper method that accepts the EF expression as an argument. This would be a trivial thing to do with SQL, but I want to do it with EF so that I can benefit from the strongly typed objects. First Example: public static User GetUser(String userEmail) { using (MyEntities dataModel = new MyEntities ()) { var query = FancyRetryLogic(() => { (dataModel.Users.FirstOrDefault<User>(x => x.UserEmail == userEmail))); }); return query; } } Second Example: T RetryHelper<T>(Expression<Func<T, TValue>> expression) { using (MyEntities dataModel = new (MyEntities ()) { var query = FancyRetryLogic(() => { return dataModel.expression }); } } public User GetUser(String userEmail) { return RetryHelper<User>(<User>.FirstOrDefault<User>(x => x.UserEmail == userEmail)) }

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  • hibernate insert to a collection causes a delete then all the items in the collection to be inserted

    - by Mark
    I have a many to may relationship CohortGroup and Employee. Any time I insert an Employee into the CohortGroup hibernate deletes the group from the resolution table and inserts all the members again, plus the new one. Why not just add the new one? The annotation in the Group: @ManyToMany(cascade = { PERSIST, MERGE, REFRESH }) @JoinTable(name="MYSITE_RES_COHORT_GROUP_STAFF", joinColumns={@JoinColumn(name="COHORT_GROUPID")}, inverseJoinColumns={@JoinColumn(name="USERID")}) public List<Employee> getMembers(){ return members; } The other side in the Employee @ManyToMany(mappedBy="members",cascade = { PERSIST, MERGE, REFRESH } ) public List<CohortGroup> getMemberGroups(){ return memberGroups; } Code snipit Employee emp = edao.findByID(cohortId); CohortGroup group = cgdao.findByID(Long.decode(groupId)); group.getMembers().add(emp); cgdao.persist(group); below is the sql reported in the log delete from swas.MYSITE_RES_COHORT_GROUP_STAFF where COHORT_GROUPID=? insert into swas.MYSITE_RES_COHORT_GROUP_STAFF (COHORT_GROUPID, USERID) values (?, ?) insert into swas.MYSITE_RES_COHORT_GROUP_STAFF (COHORT_GROUPID, USERID) values (?, ?) insert into swas.MYSITE_RES_COHORT_GROUP_STAFF (COHORT_GROUPID, USERID) values (?, ?) insert into swas.MYSITE_RES_COHORT_GROUP_STAFF (COHORT_GROUPID, USERID) values (?, ?) insert into swas.MYSITE_RES_COHORT_GROUP_STAFF (COHORT_GROUPID, USERID) values (?, ?) insert into swas.MYSITE_RES_COHORT_GROUP_STAFF (COHORT_GROUPID, USERID) values (?, ?) This seams really inefficient and is causing some issues. If sevral requests are made to add an employee to the group then some get over written.

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  • Database Programming in C#, returning output from Stored Proc

    - by jpavlov
    I am working at gaining an understanding at how to interface stored procedures with applications. My example is simple, but it doesn't display my columns and rows in the command prompt, instead it display System.Data.SqlClient.SqlDataReader. How do I display the rows from my stored procudure? ----Stored Proc-- ALTER PROCEDURE dbo.SelectID AS SELECT * FROM tb_User; ----- Below is the code: using System; using System.Data.SqlClient; using System.IO; namespace ExecuteStoredProc { class Program { static void Main(string[] args) { SqlConnection cnnUserMan; SqlCommand cmmUser; //SqlDataReader drdUser; //Instantiate and open the connection cnnUserMan = new SqlConnection("Data Source=.\\SQLEXPRESS;AttachDbFilename=c:\\Program Files\\Microsoft SQL Server\\MSSQL10.SQLEXPRESS\\MSSQL\\DATA\\UserDB.mdf; Integrated Security=True;Connect Timeout=30;User Instance=True"); cnnUserMan.Open(); //Instantiate and initialize command cmmUser = new SqlCommand("SelectID", cnnUserMan); cmmUser.CommandType = System.Data.CommandType.StoredProcedure; //drdUser = cmmUser.ExecuteReader(); Console.WriteLine(cmmUser.ExecuteReader()); Console.ReadLine(); } } } Thanks.

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  • MSMQ - Message Queue Abstraction and Pattern

    - by Maxim Gershkovich
    Hi All, Let me define the problem first and why a messagequeue has been chosen. I have a datalayer that will be transactional and EXTREMELY insert heavy and rather then attempt to deal with these issues when they occur I am hoping to implement my application from the ground up with this in mind. I have decided to tackle this problem by using the Microsoft Message Queue and perform inserts as time permits asynchronously. However I quickly ran into a problem. Certain inserts that I perform may need to be recalled (ie: retrieved) immediately (imagine this is for POS system and what happens if you need to recall the last transaction - one that still hasn’t been inserted). The way I decided to tackle this problem is by abstracting the MessageQueue and combining it in my data access layer thereby creating the illusion of a single set of data being returned to the user of the datalayer (I have considered the other issues that occur in such a scenario (ie: essentially dirty reads and such) and have concluded for my purposes I can control these issues). However this is where things get a little nasty... I’ve worked out how to get the messages back and such (trivial enough problem) but where I am stuck is; how do I create a generic (or at least somewhat generic) way of querying my message queue? One where I can minimize the duplication between the SQL queries and MessageQueue queries. I have considered using LINQ (but have very limited understanding of the technology) and have also attempted an implementation with Predicates which so far is pretty smelly. Are there any patterns for such a problem that I can utilize? Am I going about this the wrong way? Does anyone have an of their own ideas about how I can tackle this problem? Does anyone even understand what I am talking about? :-) Any and ALL input would be highly appreciated and seriously considered… Thanks again.

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  • C#: Using one Data Table in order to fill 2 different comboboxes?

    - by odiseh
    Hi all. I have 2 comboboxes on a form (form1) called combobox1 and combobox2. Each comboboxes should be filled with data stored in 2 different tables in Sql server 2005: table1 and table2 I mean: combobox1 -- table1 combobox2 -- table2 I fill data table with proper data and then bind the comboboxes to it separately. My problem is: after filling 2 combos, both of them have equal data got from table2. This is my code: DataTable tb1 = new DataTable(); //Filling tb1 with data got from table1 combobox1.Items.Clear(); combobox1.DataSource = tb1; combobox1.DisplayMember = "Name"; combobox1.ValueMember = "ID"; combobox1.SelectedIndex = -1; //filling tb1 with data got from table2 combobox2.Items.Clear(); combobox2.DataSource = tb1; combobox2.DisplayMember = "Name"; combobox2.ValueMember = "ID"; combobox2.SelectedIndex = -1; What's wrong? It seems that if I get 2 different data tables (tb1 and tb2) , every thing will be all right. Any suggestions please. Thank you

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  • Displaying a collection of objects in a .Net grid on a smartphone without data binding.

    - by Xav
    I know there's No DataGridView in the CF, but I've got a collection of in-memory objects that I want to display in a grid on a phone. Options I have thought of: Stick all the objects into a SQL-CE database and use a bound datagrid. This'll mean pulling my classes apart and separating the data from the functionality, which may or may not be a bad thing, but seems a little overkill. Write my own dataset and binding code so that I can bind my collection of objects to a bound datagrid. No idea how practical or possible this is, but seems like it's either do-able or impossible and I'm hoping someone here knows which! Find a third-party unbound grid control. The only one I've seen mentioned is OpenNetCF, which I'm downloading as I type. Are there others? Are any of them any good? Do something very nasty with dynamically loading labels and textboxes into a scrolling region on the form. REALLY don't want to go there. I'm not much experienced with data-bound controls other than occasionally making use of the very vanilla functionality in WinForms or ASP.Net, and that quite a long time ago, so if any of the above are silly, please be gentle. Thanks Xav

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  • SQLAlchemy, one to many vs many to one

    - by sadvaw
    Dear Everyone, I have the following data: CREATE TABLE `groups` ( `bookID` INT NOT NULL, `groupID` INT NOT NULL, PRIMARY KEY(`bookID`), KEY( `groupID`) ); and a book table which basically has books( bookID, name, ... ), but WITHOUT groupID. There is no way for me to determine what the groupID is at the time of the insert for books. I want to do this in sqlalchemy. Hence I tried mapping Book to the books joined with groups on book.bookID=groups.bookID. I made the following: tb_groups = Table( 'groups', metadata, Column('bookID', Integer, ForeignKey('books.bookID'), primary_key=True ), Column('groupID', Integer), ) tb_books = Table( 'books', metadata, Column('bookID', Integer, primary_key=True), tb_joinedBookGroup = sql.join( tb_books, tb_groups, \ tb_books.c.bookID == tb_groups.c.bookID) and defined the following mapper: mapper( Group, tb_groups, properties={ 'books': relation(Book, backref='group') }) mapper( Book, tb_joinedBookGroup ) ... However, when I execute this piece of code, I realized that each book object has a field groups, which is a list, and each group object has books field which is a singular assigment. I think my definition here must have been causing sqlalchemy to be confused about the many-to-one vs one-to-many relationship. Can someone help me sort this out? My desired goal is g.books = [b, b, b, .. ] book.group = g, where g is an instance of group, and b is an instance of book

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  • Improving Javascript Load Times - Concatenation vs Many + Cache

    - by El Yobo
    I'm wondering which of the following is going to result in better performance for a page which loads a large amount of javascript (jQuery + jQuery UI + various other javascript files). I have gone through most of the YSlow and Google Page Speed stuff, but am left wondering about a particular detail. A key thing for me here is that the site I'm working on is not on the public net; it's a business to business platform where almost all users are repeat visitors (and therefore with caches of the data, which is something that YSlow assumes will not be the case for a large number of visitors). First up, the standard approach recommended by tools such as YSlow is to concatenate it, compress it, and serve it up in a single file loaded at the end of your page. This approach sounds reasonably effective, but I think that a key part of the reasoning here is to improve performance for users without cached data. The system I currently have is something like this * All javascript files are compressed and loaded at the bottom of the page * All javascript files have far future cache expiration dates, so will remain (for most users) in the cache for a long time * Pages only load the javascript files that they require, rather than loading one monolithic file, most of which will not be required Now, my understanding is that, if the cache expiration date for a javascript file has not been reached, then the cached version is used immediately; there is no HTTP request sent at to the server at all. If this is correct, I would assume that having multiple tags is not causing any performance penalty, as I'm still not having any additional requests on most pages (recalling from above that almost all users have populated caches). In addition to this, not loading the JS means that the browser doesn't have to interpret or execute all this additional code which it isn't going to need; as a B2B application, most of our users are unfortunately stuck with IE6 and its painfully slow JS engine. Another benefit is that, when code changes, only the affected files need to be fetched again, rather than the whole set (granted, it would only need to be fetched once, so this is not so much of a benefit). I'm also looking at using LabJS to allow for parallel loading of the JS when it's not cached. So, what do people think is a better approach? In a similar vein, what do you think about a similar approach to CSS - is monolithic better?

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  • CultureManager issue

    - by Serge
    I have a bug I don't understand. While the following works fine: Resources.Classes.AFieldFormula.DirectFieldFormula this one throws an exception: new ResourceManager(typeof(Resources.Classes.AFieldFormula)).GetString("DirectFieldFormula"); Could not find any resources appropriate for the specified culture or the neutral culture. Make sure \"Resources.Classes.AFieldFormula.resources\" was correctly embedded or linked into assembly \"MygLogWeb\" at compile time, or that all the satellite assemblies required are loadable and fully signed. How comes? Resource designer.cs file: //------------------------------------------------------------------------------ // <auto-generated> // This code was generated by a tool. // Runtime Version:4.0.30319.18408 // // Changes to this file may cause incorrect behavior and will be lost if // the code is regenerated. // </auto-generated> //------------------------------------------------------------------------------ namespace Resources.Classes { using System; /// <summary> /// A strongly-typed resource class, for looking up localized strings, etc. /// </summary> // This class was auto-generated by the StronglyTypedResourceBuilder // class via a tool like ResGen or Visual Studio. // To add or remove a member, edit your .ResX file then rerun ResGen // with the /str option, or rebuild your VS project. [global::System.CodeDom.Compiler.GeneratedCodeAttribute("System.Resources.Tools.StronglyTypedResourceBuilder", "4.0.0.0")] [global::System.Diagnostics.DebuggerNonUserCodeAttribute()] [global::System.Runtime.CompilerServices.CompilerGeneratedAttribute()] public class AFieldFormula { private static global::System.Resources.ResourceManager resourceMan; private static global::System.Globalization.CultureInfo resourceCulture; [global::System.Diagnostics.CodeAnalysis.SuppressMessageAttribute("Microsoft.Performance", "CA1811:AvoidUncalledPrivateCode")] internal AFieldFormula() { } /// <summary> /// Returns the cached ResourceManager instance used by this class. /// </summary> [global::System.ComponentModel.EditorBrowsableAttribute(global::System.ComponentModel.EditorBrowsableState.Advanced)] public static global::System.Resources.ResourceManager ResourceManager { get { if (object.ReferenceEquals(resourceMan, null)) { global::System.Resources.ResourceManager temp = new global::System.Resources.ResourceManager("MygLogWeb.Classes.AFieldFormula", typeof(AFieldFormula).Assembly); resourceMan = temp; } return resourceMan; } } /// <summary> /// Overrides the current thread's CurrentUICulture property for all /// resource lookups using this strongly typed resource class. /// </summary> [global::System.ComponentModel.EditorBrowsableAttribute(global::System.ComponentModel.EditorBrowsableState.Advanced)] public static global::System.Globalization.CultureInfo Culture { get { return resourceCulture; } set { resourceCulture = value; } } /// <summary> /// Looks up a localized string similar to Direct field. /// </summary> public static string DirectFieldFormula { get { return ResourceManager.GetString("DirectFieldFormula", resourceCulture); } } } }

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  • Currently using View, Should I use a hard table instead?

    - by 1001010101
    I am currently debating whether my table, mapping_uGroups_uProducts, which is a view formed by the following table: CREATE ALGORITHM=UNDEFINED DEFINER=`root`@`localhost` SQL SECURITY DEFINER VIEW `db`.`mapping_uGroups_uProducts` AS select distinct `X`.`upID` AS `upID`,`Z`.`ugID` AS `ugID` from ((`db`.`mapping_uProducts_Products` `X` join `db`.`productsInfo` `Y` on((`X`.`pID` = `Y`.`pID`))) join `db`.`mapping_uGroups_Groups` `Z` on((`Y`.`gID` = `Z`.`gID`))); My current query is: SELECT upID FROM uProductsInfo \ JOIN fs_uProducts USING (upID) column \ JOIN mapping_uGroups_uProducts USING (upID) -- could be faster if we use hard table and index \ JOIN mapping_fs_key USING (fsKeyID) \ WHERE fsName="OVERALL" \ AND ugID=1 \ ORDER BY score DESC \ LIMIT 0,30; which is pretty slow. (for 30 results, it requires about 10 secondes). I think the reason for my query being so slow is definitely due to the fact that that particular query relies on a VIEW which has no index to speed things up. +----+-------------+----------------+--------+----------------+---------+---------+---------------------------------------+-------+---------------------------------+ | id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra | +----+-------------+----------------+--------+----------------+---------+---------+---------------------------------------+-------+---------------------------------+ | 1 | PRIMARY | mapping_fs_key | const | PRIMARY,fsName | fsName | 386 | const | 1 | Using temporary; Using filesort | | 1 | PRIMARY | <derived2> | ALL | NULL | NULL | NULL | NULL | 19706 | Using where | | 1 | PRIMARY | uProductsInfo | eq_ref | PRIMARY | PRIMARY | 4 | mapping_uGroups_uProducts.upID | 1 | Using index | | 1 | PRIMARY | fs_uProducts | ref | upID | upID | 4 | db.uProductsInfo.upID | 221 | Using where | | 2 | DERIVED | X | ALL | PRIMARY | NULL | NULL | NULL | 40772 | Using temporary | | 2 | DERIVED | Y | eq_ref | PRIMARY | PRIMARY | 4 | db.X.pID | 1 | Distinct | | 2 | DERIVED | Z | ref | PRIMARY | PRIMARY | 4 | db.Y.gID | 2 | Using index; Distinct | +----+-------------+----------------+--------+----------------+---------+---------+---------------------------------------+-------+---------------------------------+ 7 rows in set (0.48 sec) The explain here looks pretty cryptic, and I don't know whether I should drop view and write a script to just insert everything in the view to a hard table. ( obviously, it will lose the flexibility of the view since the mapping changes quite frequently). Does anyone have any idea to how I can optimize my schema better?

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  • How do I create a safe local development environment?

    - by docgnome
    I'm currently doing web development with another developer on a centralized development server. In the past this has worked alright, as we have two separate projects we are working on and rarely conflict. Now, however, we are adding a third (possible) developer into the mix. This is clearly going to create problems with other developers changes affecting my work and vice versa. To solve this problem, I'm thinking the best solution would be to create a virtual machine to distribute between the developers for local use. The problem I have is when it comes to the database. Given that we all develop on laptops, simply keeping a local copy of the live data is plain stupid. I've considered sanitizing the data, but I can't really figure out how to replace the real data, with data that would be representative of what people actually enter with out repeating the same information over and over again, e.g. everyone's address becomes 123 Testing Lane, Test Town, WA, 99999 or something. Is this really something to be concerned about? Are there tools to help with this sort of thing? I'm using MySQL. Ideally, if I sanitized the db it should be done from a script that I can run regularly. If I do this I'd also need a way to reduce the size of the db itself. (I figure I could select all the records created after x and whack them and all the records in corresponding tables out so that isn't really a big deal.) The second solution I've thought of is to encrypt the hard drive of the vm, but I'm unsure of how practical this is in terms of speed and also in the event of a lost/stolen laptop. If I do this, should the vm hard drive file itself be encrypted or should it be encrypted in the vm? (I'm assuming the latter as it would be portable and doesn't require the devs to have any sort of encryption capability on their OS of choice.) The third is to create a copy of the database for each developer on our development server that they are then responsible to keep the schema in sync with the canonical db by means of migration scripts or what have you. This solution seems to be the simplest but doesn't really scale as more developers are added. How do you deal with this problem?

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  • Can i change the identity of the logged in user in ASP.net?

    - by Rising Star
    I have an ASP.net application I'm developing authentication for. I am using an existing cookie-based log on system to log users in to the system. The application runs as an anonymous account and then checks the cookie when the user wants to do something restricted. This is working fine. However, there is one caveat: I've been told that for each page that connects to our SQL server, I need to make it so that the user connects using an Active Directory account. because the system I'm using is cookie based, the user isn't logged in to Active Directory. Therefore, I use impersonation to connect to the server as a specific account. However, the powers that be here don't like impersonation; they say that it clutters up the code. I agree, but I've found no way around this. It seems that the only way that a user can be logged in to an ASP.net application is by either connecting with Internet Explorer from a machine where the user is logged in with their Active Directory account or by typing an Active Directory username and password. Neither of these two are workable in my application. I think it would be nice if I could make it so that when a user logs in and receives the cookie (which actually comes from a separate log on application, by the way), there could be some code run which tells the application to perform all network operations as the user's Active Directory account, just as if they had typed an Active Directory username and password. It seems like this ought to be possible somehow, but the solution evades me. How can I make this work?

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  • What might be causing this Rails method error?

    - by Trip
    My error: Notice the undefined method '-@' . This is for a sort by. All sorts on one page break, but all the sorts on other pages use the same helper and do not break. Does it allude to something obvious? Processing OrganizationsController#search (for ::1 at 2010-05-13 15:42:01) [GET] Parameters: {"action"=>"search", "controller"=>"organizations", "direction"=>"desc", "_"=>"1273779721464", "order_by"=>"published_at"} SQL (0.5ms) SHOW TABLES Organization Columns (2.2ms) SHOW FIELDS FROM `organizations` NoMethodError (undefined method `-@' for #<Array:0x2f88cc8>): app/controllers/organizations_controller.rb:190:in `search' sunspot (1.0.5) lib/sunspot/util.rb:84:in `call' sunspot (1.0.5) lib/sunspot/util.rb:84:in `instance_eval_or_call' sunspot (1.0.5) lib/sunspot/search.rb:200:in `build' sunspot (1.0.5) lib/sunspot/session.rb:45:in `new_search' sunspot (1.0.5) lib/sunspot/session.rb:53:in `search' sunspot (1.0.5) lib/sunspot/session_proxy/abstract_session_proxy.rb:11:in `search' sunspot (1.0.5) lib/sunspot.rb:323:in `search' app/controllers/organizations_controller.rb:183:in `search' haml (2.2.2) [v] rails/./lib/sass/plugin/rails.rb:19:in `process' lib/flash_session_cookie_middleware.rb:14:in `call' vendor/gems/hoptoad_notifier-2.2.2/lib/hoptoad_notifier/rack.rb:27:in `call' /usr/local/lib/ruby/1.8/webrick/httpserver.rb:104:in `service' /usr/local/lib/ruby/1.8/webrick/httpserver.rb:65:in `run' /usr/local/lib/ruby/1.8/webrick/server.rb:173:in `start_thread' /usr/local/lib/ruby/1.8/webrick/server.rb:162:in `start' /usr/local/lib/ruby/1.8/webrick/server.rb:162:in `start_thread' /usr/local/lib/ruby/1.8/webrick/server.rb:95:in `start' /usr/local/lib/ruby/1.8/webrick/server.rb:92:in `each' /usr/local/lib/ruby/1.8/webrick/server.rb:92:in `start' /usr/local/lib/ruby/1.8/webrick/server.rb:23:in `start' /usr/local/lib/ruby/1.8/webrick/server.rb:82:in `start' Rendered rescues/_trace (68.5ms) Rendered rescues/_request_and_response (0.6ms) Rendering rescues/layout (internal_server_error)

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  • LINQ .Cast() extension method fails but (type)object works.

    - by Ben Robinson
    To convert between some LINQ to SQL objects and DTOs we have created explicit cast operators on the DTOs. That way we can do the following: DTOType MyDTO = (LinqToSQLType)MyLinq2SQLObj; This works well. However when you try to cast using the LINQ .Cast() extension method it trows an invalid cast exception saying cannot cast type Linq2SQLType to type DTOType. i.e. the below does not work List<DTO.Name> Names = dbContact.tNames.Cast<DTO.Name>() .ToList(); But the below works fine: DAL.tName MyDalName = new DAL.tName(); DTO.Name MyDTOName = (DTO.Name)MyDalName; and the below also works fine List<DTO.Name> Names = dbContact.tNames.Select(name => (DTO.Name)name) .ToList(); Why does the .Cast() extension method throw an invalid cast exception? I have used the .Cast() extension method in this way many times in the past and when you are casting something like a base type to a derived type it works fine, but falls over when the object has an explicit cast operator.

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  • Oracle 10.1 and 11.2 produce different XML using the same statement

    - by MindFyer
    I am migrating a database from Oracle 10.1 to 11.2 and I have the following problem. The statement SELECT '<?xml version="1.0" encoding="utf-8" ?>' || (Xml).getClobVal() AS XmlClob FROM ( SELECT XmlElement( "Element1", ( SELECT XmlAgg(tpx.Xml) FROM ( SELECT XmlElement("Element3",XmlForest('content' as Element4)) AS Xml FROM dual ) tpx ) AS "Element2" ) AS Xml FROM dual ) On the original 10.1 database produces XML like this... <?xml version="1.0" encoding="utf-8"?> <Element1> <Element2> <Element3> <ELEMENT4>content</ELEMENT4> </Element3> </Element2> </Element1> On the new 11.2 system it looks like this... <?xml version="1.0" encoding="utf-8"?> <Element1> <Element3> <ELEMENT4>content</ELEMENT4> </Element3> </Element1> Is there some environmental variable I am missing that tells Oracle how to format its XML. There are hundreds of thousands of lines of PL/SQL in the database; it would be a mammoth task to rewrite if it turned out they had changed they way Oracle formats XML between versions. Hopefully someone has come accross this before. Thanks

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  • (Rails) Creating multi-dimensional hashes/arrays from a data set...?

    - by humble_coder
    Hi All, I'm having a bit of an issue wrapping my head around something. I'm currently using a hacked version of Gruff in order to accommodate "Scatter Plots". That said, the data is entered in the form of: g.data("Person1",[12,32,34,55,23],[323,43,23,43,22]) ...where the first item is the ENTITY, the second item is X-COORDs, and the third item is Y-COORDs. I currently have a recordset of items from a table with the columns: POINT, VALUE, TIMESTAMP. Due to the "complex" calculations involved I must grab everything using a single query or risk way too much DB activity. That said, I have a list of items for which I need to dynamically collect all data from the recordset into a hash (or array of arrays) for the creation of the data items. I was thinking something like the following: @h={} e = Events.find_by_sql(my_query) e.each do |event| @h["#{event.Point}"][x] = event.timestamp @h["#{event.Point}"][y] = event.value end Obviously that's not the correct syntax, but that's where my brain is going. Could someone clean this up for me or suggest a more appropriate mechanism by which to accomplish this? Basically the main goal is to keep data for each pointname grouped (but remember the recordset has them all). Much appreciated. EDIT 1 g = Gruff::Scatter.new("600x350") g.title = self.name e = Event.find_by_sql(@sql) h ={} e.each do |event| h[event.Point.to_s] ||= {} h[event.Point.to_s].merge!({event.Timestamp.to_i,event.Value}) end h.each do |p| logger.info p[1].values.inspect g.data(p[0],p[1].keys,p[1].values) end g.write(@chart_file)

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  • Where are the network boundaries in the Java Connector Architecture (JCA)?

    - by Laird Nelson
    I am writing a JCA resource adapter. I'm also, as I go, trying to fully understand the connection management portion of the JCA specification. As a thought experiment, pretend that the only client of this adapter will be a Swing Java Application Client located on a different machine. Also assume that the resource adapter will communicate with its "enterprise information system" (EIS) over the network as well. As I understand the JCA specification, the .rar file is deployed to the application server. The application server creates the .rar file's implementation of the ManagedConnectionFactory interface. It then asks it to produce a connection factory, which is the opaque object that is deployed to JNDI for the user to use to obtain a connection to the resource. (In the case of JDBC, the connection factory is a javax.sql.DataSource.) It is a requirement that the connection factory retain a reference to the application-server-supplied ConnectionManager, which, in turn, is required to be Serializable. This makes sense--in order for the connection factory to be stored in JNDI, it must be serializable, and in order for it to keep a reference to the ConnectionManager, the ConnectionManager must also be serializable. So fine, this little object graph gets installed in the application client's JNDI tree. This is where I start to get queasy. Is the ConnectionManager--the piece supplied by the application server that is supposed to handle connection management, sharing, pooling, etc.--wholly present on the client at this point? One of its jobs is to create ManagedConnection instances, and a ManagedConnection is not required to be Serializable, and the user connection handles it vends are also not required to be Serializable. That suggests to me that the whole connection pooling machinery is shipped wholesale to the application client and stuffed into its JNDI tree. Does this all mean that JCA interactions from the client side bypass the server-side componentry of the application server? Where are the network boundaries in the JCA API?

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  • Generate A Simple Read-Only DAL?

    - by David
    I've been looking around for a simple solution to this, trying my best to lean towards something like NHibernate, but so far everything I've found seems to be trying to solve a slightly different problem. Here's what I'm looking at in my current project: We have an IBM iSeries database as a primary repository for a third party software suite used for our core business (a financial institution). Part of what my team does is write applications that report on or key off of a lot of this data in some way. In the past, we've been manually creating ADO .NET connections (we're using .NET 3.5 and Visual Studio 2008, by the way) and manually writing queries, etc. Moving forward, I'd like to simplify the process of getting data from there for the development team. Rather than creating connections and queries and all that each time, I'd much rather a developer be able to simply do something like this: var something = (from t in TableName select t); And, ideally, they'd just get some IQueryable or IEnumerable of generated entities. This would be done inside a new domain core that I'm building where these entities would live and the applications would interface with it through a request/response service layer. A few things to note are: The entities that correspond to the database tables should be generated once and we'd prefer to manually keep them updated over time. That is, if columns/tables are added to the database then we shouldn't have to do anything. (If some are deleted, of course, it will break, but that's fine.) But if we need to use a new column, we should be able to just add it to the necessary class(es) without having to re-gen the whole thing. The whole thing should be SELECT-only. We're not doing a full DAL here because we don't want to be able to break anything in the database (even accidentally). We don't need any kind of mapping between our domain objects and the generated entity types. The domain barely covers a fraction of the data that's in there, most of it we'll never need, and we would rather just create re-usable maps manually over time. I already have a logical separation for the DAL where my "repository" classes return domain objects, I'm just looking for a better alternative to manual ADO to be used inside the repository classes. Any suggestions? It seems like what I'm doing is just enough outside the normal demand for DAL/ORM tools/tutorials online that I haven't been able to find anything. Or maybe I'm just overlooking something obvious?

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  • .NET Free memory usage (how to prevent overallocation / release memory to the OS)

    - by Ronan Thibaudau
    I'm currently working on a website that makes large use of cached data to avoid roundtrips. At startup we get a "large" graph (hundreds of thouthands of different kinds of objects). Those objects are retrieved over WCF and deserialized (we use protocol buffers for serialization) I'm using redgate's memory profiler to debug memory issues (the memory didn't seem to fit with how much memory we should need "after" we're done initializing and end up with this report Now what we can gather from this report is that: 1) Most of the memory .NET allocated is free (it may have been rightfully allocated during deserialisation, but now that it's free, i'd like for it to return to the OS) 2) Memory is fragmented (which is bad, as everytime i refresh the cash i need to redo the memory hungry deserialisation process and this, in turn creates large object that may throw an OutOfMemoryException due to fragmentation) 3) I have no clue why the space is fragmented, because when i look at the large object heap, there are only 30 instances, 15 object[] are directly attached to the GC and totally unrelated to me, 1 is a char array also attached directly to the GC Heap, the remaining 15 are mine but are not the cause of this as i get the same report if i comment them out in code. So my question is, what can i do to go further with this? I'm not really sure what to look for in debugging / tools as it seems my memory is fragmented, but not by me, and huge amounts of free spaces are allocated by .net , which i can't release. Also please make sure you understand the question well before answering, i'm not looking for a way to free memory within .net (GC.Collect), but to free memory that is already free in .net , to the system as well as to defragment said memory. Note that a slow solution is fine, if it's possible to manually defragment the large heap i'd be all for it as i can call it at the end of RefreshCache and it's ok if it takes 1 or 2 second to run. Thanks for your help! A few notes i forgot: 1) The project is a .net 2.0 website, i get the same results running it in a .net 4 pool, idem if i run it in a .net 4 pool and convert it to .net 4 and recompile. 2) These are results of a release build, so debug build can not be the issue. 3) And this is probably quite important, i do not get these issues at all in the webdev server, only in IIS, in the webdev i get memory consumption rather close to my actual consumption (well more, but not 5-10X more!)

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  • What's best choice career-wise, to know a little about a lot or a lot about a little?

    - by nimo
    I work as a developer at a rather small company and we are providing a web application that is used by a big base of customers. Because we are so small everyone have to be able to do a lot of different tasks. It ranges from advanced support, developing the product (programming: c/c++, c#, php, sql, javascript, html, css), handle network configuration and network related issues and even sometimes go on sales meetings with potential customers. My concern is that I don't really specialize in any specific area. I know and learn little about a lot. I have graduated from school two years ago and this is my first real employment and when I look at other positions out there they always require so and so many years of experience in a specific area (for example 5 years of C#). For me to get that kind of specialized experience will be really hard at my current job. My question for you is what is, in your opinion, best choice career-wise, to know a little about a lot or a lot about a little? What path did you take? pros and cons that comes with that choice.

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  • Entity framework self referencing loop detected

    - by Lyd0n
    I have a strange error. I'm experimenting with a .NET 4.5 Web API, Entity Framework and MS SQL Server. I've already created the database and set up the correct primary and foreign keys and relationships. I've created a .edmx model and imported two tables: Employee and Department. A department can have many employees and this relationship exists. I created a new controller called EmployeeController using the scaffolding options to create an API controller with read/write actions using Entity Framework. In the wizard, selected Employee as the model and the correct entity for the data context. The method that is created looks like this: // GET api/Employee public IEnumerable<Employee> GetEmployees() { var employees = db.Employees.Include(e => e.Department); return employees.AsEnumerable(); } When I call my API via /api/Employee, I get this error: ...The 'ObjectContent`1' type failed to serialize the response body for content type 'application/json; ...System.InvalidOperationException","StackTrace":null,"InnerException":{"Message":"An error has occurred.","ExceptionMessage":"Self referencing loop detected with type 'System.Data.Entity.DynamicProxies.Employee_5D80AD978BC68A1D8BD675852F94E8B550F4CB150ADB8649E8998B7F95422552'. Path '[0].Department.Employees'.","ExceptionType":"Newtonsoft.Json.JsonSerializationException","StackTrace":" ... Why is it self referencing [0].Department.Employees? That doesn't make a whole lot of sense. I would expect this to happen if I had circular referencing in my database but this is a very simple example. What could be going wrong?

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  • Best practices for (over)using Azure queues

    - by John
    Hi, I'm in the early phases of designing an Azure-based application. One of the things that attracts me to Azure is the scalability, given the variability of the demand I'm likely to expect. As such I'm trying to keep things loosely coupled so I can add instances when I need to. The recommendations I've seen for architecting an application for Azure include keeping web role logic to a minimum, and having processing done in worker roles, using queues to communicate and some sort of back-end store like SQL Azure or Azure Tables. This seems like a good idea to me as I can scale up either or both parts of the application without any issue. However I'm curious if there are any best practices (or if anyone has any experiences) for when it's best to just have the web role talk directly to the data store vs. sending data by the queue? I'm thinking of the case where I have a simple insert to do from the web role - while I could set this up as a message, send it on the queue, and have a worker role pick it up and do the insert, it seems like a lot of double-handling. However I also appreciate that it may be the case that this is better in the long run, in case the web role gets overwhelmed or more complex logic ends up being required for the insert. I realise this might be a case where the answer is "it depends entirely on the situation, check your perf metrics" - but if anyone has any thoughts I'd be very appreciative! Thanks John

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  • What is the best way to do scoped finds based on access control rules in Rails?

    - by Rafael Szuminski
    Hi I need to find an elegant solution to scoped finds based on access control rules. Essentially I have the following setup: Users Customers AccessControl - Defines which user has access to another users data Users need to be able to access not just their own customers but also shared customers of other users. Obviously something like a simple association will not work: has_many :customers and neither will this: has_many :customers, :conditions => 'user_id in (1,2,3,4,5)' because the association uses with_scope and the added condition is an AND condition not an OR condition. I also tried overriding the find and method_missing methods with the association extension like this: has_many :customers do def find(*args) #get the user_id and retrieve access conditions based on the id #do a find based on the access conditions and passed args end def method_missing(*args) #get the user_id and retrieve access conditions based on the id #do a find based on the access conditions and passed args end end but the issue is that I don't have access to the user object / parent object inside the extension methods and it just does not work as planned. I also tried default_scope but as posted here before you can't pass a block to a default scope. Anyhow, I know that data segmentation and data access controls have been done before using rails and am wondering if somebody found an elegant way to do it. UPDATE: The AccessControl table has the following layout user_id shared_user_id The customer table has this structure: id account_id user_id first_name last_name Assuming the the following data would be in the AccessControl table: 1 1 1 3 1 4 2 2 2 13 and so on... And the account_id for user 1 is 13 I need to be able to retrieve customers that can be best described with the following sql statement: select * from customers where (account_id = 13 and user_id = null) or (user_id in (1,3,4))

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  • Call Oracle package function using Odbc from C#

    - by Paolo Tedesco
    I have a function defined inside an Oracle package: CREATE OR REPLACE PACKAGE BODY TESTUSER.TESTPKG as FUNCTION testfunc(n IN NUMBER) RETURN NUMBER as begin return n + 1; end testfunc; end testpkg; / How can I call it from C# using Odbc? I tried the following: using System; using System.Data; using System.Data.Odbc; class Program { static void Main(string[] args) { using (OdbcConnection connection = new OdbcConnection("DSN=testdb;UID=testuser;PWD=testpwd")) { connection.Open(); OdbcCommand command = new OdbcCommand("TESTUSER.TESTPKG.testfunc", connection); command.CommandType = System.Data.CommandType.StoredProcedure; command.Parameters.Add("ret", OdbcType.Int).Direction = ParameterDirection.ReturnValue; command.Parameters.Add("n", OdbcType.Int).Direction = ParameterDirection.Input; command.Parameters["n"].Value = 42; command.ExecuteNonQuery(); Console.WriteLine(command.Parameters["ret"].Value); } } } But I get an exception saying "Invalid SQL Statement". What am I doing wrong?

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  • AJAX filter MySQL results using checkboxes

    - by keepitnang
    I'm attempting to get to grips with displaying filterable MySQL data within a PHP page based on user checkbox selections. I have a database of domain names and the dates on which these will require renewal as per Nominet DAC information and I can get unfiltered data to display, but filtering results by domain extensions is proving tricky for me to accomplish. I should point out at this stage that I am a serious newcomer to many of the ideas I am trying to learn to work with here, so please be gentle. I have tried following some other articles on here also, but no dice. I have the following so far: HTML <input type="checkbox" class="extensions" name="extensions" value=".co.uk">.co.uk</input> <input type="checkbox" class="extensions" name="extensions" value=".org.uk">.org.uk</input> Script $('.extensions').live('click', function() { var all_boxes = $('.extensions'); var all_boxes_values = []; var i = 0; for (var i; i < all_boxes.length; i++) { if (all_boxes[i].checked) { all_boxes_values.push(all_boxes[i].value) } } var all_boxes_values_clean = all_boxes_values.join(", "); console.log(all_boxes_values_clean); $.get("sql-test.php", {q: all_boxes_values_clean}, function(result) { $("div#output").html(result); } )}); PHP $g = $_GET['q']; $extensionsql=""; $extension=1; if(isset($g)) { $extension=1; $param = "" . str_replace(",", "','", $_GET['q']) . ""; } And that's as far as I have gotten with my limited ability. What I would like to do next is search the column domainName for a string match and return the appropriate results to the user. Something to mimic something like the following but I'm not sure how to achieve it. Any help would be much appreciated: SELECT * FROM `refresh` WHERE `domainName` LIKE '%.co.uk%' AND renewalDate LIKE '%2012-06-30%' ORDER BY `domainName` ASC Thanks

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