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• Associate new Authlogic Model to existing Models

  - by BriteLite

  Hello, While playing around with Rails (since I am a newbie) while reading Agile Rails book I came across an issue using the Gem Authlogic that I don't know how to address. I have a simple business Model. The tables store the following information: Name, Address, Latitude, and Longitude. The above approach has been working fine, because using the console I can enter the information and it shows up, where I need it to. My issue now is that I want to add authentication to it. As in assign those records in the table, to individual accounts. Since Authlogic is an authentication gem, can this be done? What I am trying to get to here is that, I enter a few records and leave it at that. Few days later, I want to assign those individual rows in the table to an authlogic model so the person to whom the record should belong can authenticate to it and make changes. Any code samples, blog posts to better help me understand would be great! Thank You.

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• Foreign key not working in MySQL: Why can I INSERT a value that's not in the foreign column?

  - by stalepretzel

  I've created a table in MySQL: CREATE TABLE actions ( A_id int NOT NULL AUTO_INCREMENT, type ENUM('rate','report','submit','edit','delete') NOT NULL, Q_id int NOT NULL, U_id int NOT NULL, date DATE NOT NULL, time TIME NOT NULL, rate tinyint(1), PRIMARY KEY (A_id), CONSTRAINT fk_Question FOREIGN KEY (Q_id) REFERENCES questions(P_id), CONSTRAINT fk_User FOREIGN KEY (U_id) REFERENCES users(P_id)); This created the table I wanted just fine (although a "DESCRIBE actions;" command showed me that the foreign keys were keys of type MUL, and I'm not sure what this means). However, when I try to enter a Q_id or a U_id that does not exist in the questions or users tables, MySQL still allows these values. What did I do wrong? How can I prevent a table with a foreign key from accepting invalid data? If I add TYPE=InnoDB to the end, I get an error: ERROR 1005 (HY000): Can't create table './quotes/actions.frm' (errno: 150) Why might that happen? I'm told that it's important to enforce data integrity with functional foreign keys, but also that InnoDB should not be used with MySQL. What do you recommend?

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• Changing character encoding in MySQL, PHP scripts, HTML

  - by Sandman

  So, I have built on this system for quite some time, and it is currently outputting Latin1 (ISO-8859-1) to the web browser, and this is the components: MySQL - all data is stored with the Latin1 character set PHP - All PHP text files are stored on disk with Latin1 encoding HTML - The output has the http-equiv="content-type" content="text/html; charset=iso-8859-1" meta tag So, I'm trying to understand how the encoding of the different parts come into play in my workflow. If I open a PHP script and change its encoding within the text editor to UTF-8 and save it back to disk and reload the web browser, the text is all messed up - unless the text comes from the DB. If I change the encoding of the DB to UTF-8 and keep the PHP files in latin1 I have to use utf8_decode() for the data to display correctly. And if I change the HTML code the browser will read it incorrectly. So yeah, I realise that if I want to "upgrade" to UTF8, I have to update all three parts of this setup for it to work correctly, but since it's a huge system with some 180k lines of PHP code and millions of posts in a lot of databases/tables, I don't want to start something like this without understanding everything correctly. What haven't I thought about? What could mess this up beyond fixing? What are the procedures for changing the encoding of an entire MySQL installation and what's the easiest way to change the encoding of hundreds or thousands of PHP files on disk? The META tag is luckily added dynamically, so I'll change that in one place only :) Let me hear about your experiences with this.

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• SQL, MVC, Entity Framework

  - by Anthony

  Hi Im using the above technologies and have ran into what I presume is a design issue I have made. I have an Artwork table in my DB and have been able to add art (I now think of these as Digital Products) to a shopping cart + CartLine table fine. The system I have that adds art to galleries and user accounts etc works fine. Now the client wants to sell T-shirts, Mugs and Pens etc, 'HardwareProducts' so I have created a 'HardwareProducts' table. Now I have two different product types in two tables. I use GUID's as the PK's in both the HardwareProducts table and Artwork table. When a customer adds an item to their cart I store the GUID in the ProductID column in the CartItems table. The issue is the database will not know which table to reference when I bring the LineItem object up through my ORM to the front end. In OOP I can see how you would have a base class of Product, and then a DigitalProduct class and HardwareProduct class drived from it, but how do you model this in SQL Server and the Entity Framework please, or is there another way?

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• complex web forms and javascript

  - by Casey

  I need to create a few data heavy complicated forms. Currently, the information is being entered into a spread sheet, but the users will need to enter the information into the online form where it will be saved to a database. The problem is that the business users currently using the spread sheet aren't going to want to use the online application if it isn't as easy as entering the information into the spread sheet. This is further complicated in that the information they are entering into the spread sheet is represented by three different DB tables where one "object" is composed of two of the others. I would prefer to not have them have to go through multiple forms. Some of what I have been thinking is: Use of auto complete where possible Hiding/removing form fields dynamically possible wizard style page flow?? I've been googling for other data heavy web forms but can't seem to really find any good examples. I am familiar with jQuery and prototypejs and have also tried googling for frameworks designed for data heavy applications but didn't come up with anything. Any thoughts? Thanks.

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• SQL Design: representing a default value with overrides?

  - by Mark Harrison

  I need a sparse table which contains a set of "override" values for another table. I also need to specify the default value for the items overridden. For example, if the default value is 17, then foo,bar,baz will have the values 17,21,17: table "things" table "xvalue" name stuff name xval ---- ----- ---- ---- foo ... bar 21 bar ... baz ... If I don't care about a FK from xvalue.name - things.name, I could simply put a "DEFAULT" name: table "xvalue" name xval ---- ---- DEFAULT 17 bar 21 But I like having a FK. I could have a separate default table, but it seems odd to have 2x the number of tables. table "xvalue_default" xval ---- 17 table "xvalue" name xval ---- ---- bar 21 I could have a "defaults table" tablename attributename defaultvalue xvalue xval 17 but then I run into type issues on defaultvalue. My operations guys prefer as compact a representation as possible, so they can most easily see the "diff" or deviations from the default. What's the best way to represent this, including the default value? This will be for Oracle 10.2 if that makes a difference.

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• mysqldb interfaceError

  - by Johanna

  I have a very weird probleme with mysqldb (mysql module for python). I have a file with queries for inserting records in tables. If I call the functions from the file, it works just fine. But when I try to call one of the functions from another file it throws me a _mysql_exception.InterfaceError: (0, '') I really don't get what I'm doing wrong here.. I call the function from buildDB.py : import create create.newFormat("HD", 0,0,0) The function newFormat(..) is in create.py (imported) : from Database import Database db = Database() def newFormat(name, width=0, height=0, fps=0): format_query = "INSERT INTO Format (form_name, form_width, form_height, form_fps) VALUES ('"+name+"',"+str(width)+","+str(height)+","+str(fps)+");" db.execute(format_query) And the class Databse is the following : import MySQLdb from MySQLdb.constants import FIELD_TYPE class Database(): def __init__(self): server = "localhost" login = "seq" password = "seqmanager" database = "Sequence" my_conv = { FIELD_TYPE.LONG: int } self.conn = MySQLdb.connection(host=server, user=login, passwd=password, db=database, conv=my_conv) # self.cursor = self.conn.cursor() def close(self): self.conn.close() def execute(self, query): self.conn.query(query) (I put only relevant code) Traceback : Z:\sequenceManager\mysql>python buildDB.py D:\ProgramFiles\Python26\lib\site-packages\MySQLdb\__init__.py:34: DeprecationWa rning: the sets module is deprecated from sets import ImmutableSet INSERT INTO Format (form_name, form_width, form_height, form_fps) VALUES ('HD',0 ,0,0); Traceback (most recent call last): File "buildDB.py", line 182, in <module> create.newFormat("HD") File "Z:\sequenceManager\mysql\create.py", line 52, in newFormat db.execute(format_query) File "Z:\sequenceManager\mysql\Database.py", line 19, in execute self.conn.query(query) _mysql_exceptions.InterfaceError: (0, '') The warning has never been a problem before so I don't think it's related.

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• Using nohup mysqldump from php script is inserting a '!' and breaking to a new line.

  - by Aglystas

  I'm trying to run a mysqldump from php using the nohup command to prevent the script from hanging. Here's the command (The database is mc6_erik_test, everything else is just a table list until you get to the end) exec("mysqldump -u root -pPassword -h vfmy1-dev.mountainmedia.com mc6_erik_test access_log admin affiliate affiliate_2_product authorized_ip category category_2_product claim_code claim_code_log country_exclude customer customer_2_subscription customer_account_log customer_address customer_bill customer_discount customer_ip customer_key email_bulk_log email_draft email_queue email_queue_log email_template endicia_log gift_wrap image_bulk_upload log mailing_list manufacturer merchant merchant_checkout merchant_ip merchant_ship merchant_ship_conf new_account_temp order_dest order_item order_item_2_dest order_item_2_package order_item_log order_item_registrant order_note order_package order_package_label orders package package_2_product pref product product_2_supplier product_also product_event_date product_image product_option product_related product_review product_review_helpful product_ship_disable report search_log subscription supplier temp_product transaction_account transactions wish_list wish_list_fill wish_list_item --opt --where='merchant_id=\'6\'' /tmp/sync_db_card_20100519105358.sql"); As you can see it's really long, because I have to specifically include only the tables I want to dump. The command works great from the command line, however when I run it through a web script towards the end the following is being used as the command... supplier temp_product transaction_account transactio! ns wish_list wish_list_fill wish_list_item --opt --where='merchant_id="6"' > /tmp/sync_db_card_20100519105358.sql So the table 'transactions' is being split by an exclamation point and newline. The rest of the command is exactly the same. And if I run this through the php-cli interface it doesn't happen only when I try running it via the webserver using nohup. I'm wondering if there is some inherit string length to using the exec command within a php script, or really if anyone has any general idea what is going on here.

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• How to model parent to child pair in MySQL (SQL)

  - by mikeschuld

  I have a data model that includes element types Stage, Actor, and Form. Logically, Stages can be assigned pairs of ( Form <--- Actor ) which can be duplicated many times (i.e. same person and same form added to the same stage at a later date/time). Right now I am modeling this with these tables: Stage Form Actor Form_Actor _______________ |Id | |FormId | --> Id in Form |ActorId | --> Id in Actor Stage_FormActor __________________ |Id | |StageId | --> Id in Stage |FormActorId | --> Id in Form_Actor I am using CodeSmith to generate the data layer for this setup and none of the templates really know how to handle this type of relationship correctly when generating classes. Ideally, the ORM would have Stage.FormActors where FormActor would be the pair Form, Actor. Is this the correct way to model these relationships. I have tried using all three Ids in one table as well Stage_Form_Actor ______________ |Id | |StageId | --> Id in Stage |FormId | --> Id in Form |ActorId | --> Id in Actor This doesn't really get generated very well either. Ideas?

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• Understanding MongoDB(and NoSQL in general) and How to make the best use of it

  - by Earlz

  Hello, I am beginning to think that my next project I am wanting to do would work better with a NoSQL solution. The project would either involve a ton of 2-column tables or a ton of dynamic queries with dynamically generated columns in a traditional SQL database. So I feel a NoSQL database would be much cleaner. I'm looking at MongoDB and it looks pretty promising. Anyway, I'm attempting to make sense of it all. Also, I will be using MongoMapper in Ruby. Anyway though, I'm confused as to how to layout things in such a freeform database. I've read http://stackoverflow.com/questions/2170152/nosql-best-practices and the answer there says that normalization is usually bad in a NoSQL DB. So how would be the best way of laying out say a simple blog with users, posts, and comments? My natural thought was to have 3 collections for each and then link them by a unique ID. But this apparently is wrong? So, what are some of the ways to lay out such a thing? My concern with the answer given in the other question is what if the author's name changed. You'd have to go through updating a ton of posts and comments. But is this an ok thing to do with NoSQL?

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• Windows SQL wildcards and ASP.net parameters

  - by Vinzcent

  Hey In my SQL statement I use wildcards. But when I try to select something, it never select something. While when I execute the querry in Microsoft SQL Studio, it works fine. What am I doing wrong? Click handler protected void btnTitelAuteur_Click(object sender, EventArgs e) { cvalTitelAuteur.Enabled = true; cvalTitelAuteur.Validate(); if (Page.IsValid) { objdsSelectedBooks.SelectMethod = "getBooksByTitleAuthor"; objdsSelectedBooks.SelectParameters.Clear(); objdsSelectedBooks.SelectParameters.Add(new Parameter("title", DbType.String)); objdsSelectedBooks.SelectParameters.Add(new Parameter("author", DbType.String)); objdsSelectedBooks.Select(); gvSelectedBooks.DataBind(); pnlZoeken.Visible = false; pnlKiezen.Visible = true; } } In my Data Acces Layer public static DataTable getBooksByTitleAuthor(string title, string author) { string sql = "SELECT 'AUTHOR' = tblAuthors.FIRSTNAME + ' ' + tblAuthors.LASTNAME, tblBooks.*, tblGenres.GENRE " + "FROM tblAuthors INNER JOIN tblBooks ON tblAuthors.AUTHOR_ID = tblBooks.AUTHOR_ID INNER JOIN tblGenres ON tblBooks.GENRE_ID = tblGenres.GENRE_ID " +"WHERE (tblBooks.TITLE LIKE '%@title%');"; SqlDataAdapter da = new SqlDataAdapter(sql, GetConnectionString()); da.SelectCommand.Parameters.Add("@title", SqlDbType.Text); da.SelectCommand.Parameters["@title"].Value = title; DataSet ds = new DataSet(); da.Fill(ds, "Books"); return ds.Tables["Books"]; } Thanks, Vincent

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• SQL Server Express performance issue

  - by Developer IT

  Hi folks ! I know my questions will sound silly and probably nobody will have perfect answer but since I am in a complete dead-end with the situation it will make me feel better to post it here. So... I have a SQL Server Express database that's 500 Mb. It contains 5 tables and maybe 30 stored procedure. This database is use to store articles and is use for the Developer It web site. Normally the web pages load quickly, let's say 2 ou 3 sec. BUT, sqlserver process uses 100% of the processor for those 2 or 3 sec. I try to find which stored procedure was the problem and I could not find one. It seems like every read into the table dans contains the articles (there are about 155,000 of them and 20 or so gets added every 15 minutes). I added few index but without luck... It is because the table is full text indexed ? Should I have order with the primary key instead of date ? I never had any problems with ordering by dates.... Should I use dynamic SQL ? Should I add the primary key into the url of the articles ? Should I use mutiple indexes for seperate columns or one big index ? I you want more details or code bits, just ask for it. Basicly, every little hint is much apreciated. Thanks.

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• PostgreSQL, Foreign Keys, Insert speed & Django

  - by Miles

  A few days ago, I ran into an unexpected performance problem with a pretty standard Django setup. For an upcoming feature, we have to regenerate a table hourly, containing about 100k rows of data, 9M on the disk, 10M indexes according to pgAdmin. The problem is that inserting them by whatever method literally takes ages, up to 3 minutes of 100% disk busy time. That's not something you want on a production site. It doesn't matter if the inserts were in a transaction, issued via plain insert, multi-row insert, COPY FROM or even INSERT INTO t1 SELECT * FROM t2. After noticing this isn't Django's fault, I followed a trial and error route, and hey, the problem disappeared after dropping all foreign keys! Instead of 3 minutes, the INSERT INTO SELECT FROM took less than a second to execute, which isn't too surprising for a table <= 20M on the disk. What is weird is that PostgreSQL manages to slow down inserts by 180x just by using 3 foreign keys. Oh, disk activity was pure writing, as everything is cached in RAM; only writes go to the disks. It looks like PostgreSQL is working very hard to touch every row in the referred tables, as 3MB/sec * 180s is way more data than the 20MB this new table takes on disk. No WAL for the 180s case, I was testing in psql directly, in Django, add ~50% overhead for WAL logging. Tried @commit_on_success, same slowness, I had even implemented multi row insert and COPY FROM with psycopg2. That's another weird thing, how can 10M worth of inserts generate 10x 16M log segments? Table layout: id serial primary, a bunch of int32, 3 foreign keys to small table, 198 rows, 16k on disk large table, 1.2M rows, 59 data + 89 index MB on disk large table, 2.2M rows, 198 + 210MB So, am I doomed to either drop the foreign keys manually or use the table in a very un-Django way by defining saving bla_id x3 and skip using models.ForeignKey? I'd love to hear about some magical antidote / pg setting to fix this.

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• Optimzing TSQL code

  - by adopilot

  My job is the maintain one application which heavy use SQL server (MSSQL2005). Until now middle server stores TSQL codes in XML and send dynamic TSQL queries without using stored procs. As I am able change those XML queries I want to migrate most of my queries to stored procs. Question is folowing: Most of my queries have same Where conditions against one table Sample: Select ..... from .... where .... and (a.vrsta_id = @vrsta_id or @vrsta_id = 0) and (a.podvrsta_id = @podvrsta_id or @podvrsta_id = 0) and (a.podgrupa_2 = @podgrupa2_id or @podgrupa2_id = 0) and ( (a.id in (select art_id from osobina_veze where podosobina_id in (select ado from dbo.fn_ado_param_int(@podosobina)) group by art_id having count(art_id)= @podosobina_count )) or ('0' = @podosobina) ) They also have same where conditions on other table. How I should organize my code ? What is proper way ? Should I make table valued function that I will use in all queries or use #Temp tables and simple inner join my query to that each time when proc executing? or use #temp filed by table valued function ? or leave all queries with this large where clause and hope that index is going to do their jobs. or use WITH(statement)

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• PHP / Zend Framework: Force prepend table name to column name in result array?

  - by Brian Lacy

  I am using Zend_Db_Select currently to retrieve hierarchical data from several joined tables. I need to be able to convert this easily into an array. Short of using a switch statement and listing out all the columns individually in order to sort the data, my thought was that if I could get the table names auto-prepended to the keys in the result array, that would solve my problem. So considering the following (assembled) SQL: SELECT user.*, contact.* FROM user INNER JOIN contact ON contact.user_id = user.user_id I would normally get a result array like this: [username] => 'bob', [contact_id] => 5, [user_id] => 2, [firstname] => 'bob', [lastname] => 'larsen' But instead I want this: [user.user_id] => 2, [user.username] => 'bob', [contact.contact_id] => 5, [contact.firstname] => 'bob', [contact.lastname] => 'larsen' Does anyone have an idea how to achieve this? Thanks!

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• Connecting to database on web host in Visual Studio

  - by Anders Svensson

  I have a web site developed locally with a local Sql Server database. I also have a web host that provides one Sql Server database for my site. Now I want to deploy the application, and I would like to be able to manage the remote database from the Server Explorer in Visual Studio. I have the connection string used in the application, which works fine for adding, say, a datasource to a control etc. But I don't know if there's any way to use it to connect the database inside the Server Explorer so that I can add tables etc. I have read that you're supposed to be able to this instead of using the Sql Server Management Studio, but I have'nt read anything about how to connect to the remote database in it. What I have tried so far is this: I have selected Add database in Server Explorer. This brings up first a dialog where I choose Sql Server. And then I get a dialog where I can set Server name (which I tried using the ip address in the connection string below), and Authentication (where I chose Sql Server Authentication, with the user id and password from below). But when I test the connection it fails. Here's the connection string, which works fine when used for datasources in the application (obviously with different user name and password): Any help appreciated!

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• Yii user rights extension

  - by jailed abroad

  i have installed the yii rights extension and here is my code after installation, database tables are created after installation. 'modules'=>array( // uncomment the following to enable the Gii tool 'rights'=>array( 'superuserName'=>'Admin', // Name of the role with super user privileges. 'authenticatedName'=>'Authenticated', //// Name of the authenticated user role. 'userIdColumn'=>'id',// Name of the user id column in the database. 'userNameColumn'=>'username', // Name of the user name column in the database. 'enableBizRule'=>true, // Whether to enable authorization item business rules. 'enableBizRuleData'=>false, //Whether to enable data for business rules. 'displayDescription'=>true, // Whether to use item description instead of name. ' // Key to use for setting success flash messages. 'flashErrorKey'=>'RightsError', / Key to use for setting error flash messages. // 'install'=>true, // Whether to install rights. 'baseUrl'=>'/rights', // Base URL for Rights. Change if module is nested. 'layout'=>'rights.views.layouts.main', // Layout to use for displaying Rights. 'appLayout'=>'application.views.layouts.main', //Application layout. 'cssFile'=>'rights.css', // Style sheet file to use for Rights. ' 'install'=>false, // Whether to enable installer. 'debug'=>false, ), 'gii'=>array( 'class'=>'system.gii.GiiModule', 'password'=>'1234', // If removed, Gii defaults to localhost only. Edit carefully to taste. 'ipFilters'=>array('127.0.0.1','::1'), ), ), But when i type url http://localhost/rightsTest/index.php/rights then it says There must be at least one superuser! I have tried many things but unable to find answer. Thanks for your help.

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• Is it possible to use SqlGeography with Linq to Sql?

  - by cofiem

  I've been having quite a few problems trying to use Microsoft.SqlServer.Types.SqlGeography. I know full well that support for this in Ling to Sql is not great. I've tried numerous ways, beginning with what would the expected way (Database type of geography, CLR type of SqlGeography). This produces the NotSupportedException, which is widely discussed via blogs. I've then gone down the path of treating the geography column as a varbinary(max), as geography is a UDT stored as binary. This seems to work fine (with some binary reading and writing extension methods). However, I'm now running into a rather obscure issue, which does not seem to have happened to many other people. System.InvalidCastException: Unable to cast object of type 'Microsoft.SqlServer.Types.SqlGeography' to type 'System.Byte[]'. This error is thrown from an ObjectMaterializer when iterating through a query. It seems to only occur when the tables containing geography columns are included in a query implicitly (ie. using the EntityRef<> properties to do joins). System.Data.Linq.SqlClient.ObjectReaderCompiler.ObjectReader`2.MoveNext() My question: If I'm retrieving the geography column as varbinary(max), I might expect the reverse error: can't cast byte[] to SqlGeography. That I would understand. This I don't. I do have some properies on the partial LINQ to SQL classes that hide the binary conversion... could those be the issue? Any help appreciated, and I know there's probably not enough information.

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• Best way to handle Many-to-Many relationships in PHP MySQL

  - by Jayrox

  I am looking for the best way to handle a database of many-to-many relationships in PHP and MySQL. Right now I have 2 tables: Users (id, user_name, first_name, last_name) Connections (id_1, id_2) In the User table id is auto incremented on add and user_name is unique, but can be changed. Unfortunately, I don't have control over the user_name and its ability to be changed, but I must account for it. The Connections table is obviously, user1 and user2's id. The connection table needs to account for these possible relations: user1 --> user2 (user 1 friends with user 2 but not user2 friends with user1) user2 --> user1 (user 2 friends with user 1 but not user1 friends with user2) user1 <--> user2 (user 1 and user 2 mutually friends) user1 <-!-> user2 (user 1 and user 2 not friends) That part is not the problem, The problem I am having with is keeping these relations unique when and if they change in batches. Possible solution 1: delete all of user 1's relations and readd them with the updated list. I think this might be too slow for my needs. Solution 2? Anyone else encounter this problem? How should I best handle this? update: distinguishing relationships: i handle relationships like this: user1, user2 user1, user3 user2, user1 in that example the following is true: user1 follows user2 and user3 user2 only follows user1 but doesn't follow user3 user3 doesn't follow either user1 or user2

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• Database nesting layout confusion

  - by arzon

  I'm no expert in databases and a beginner in Rails, so here goes something which kinda confuses me... Assuming I have three classes as a sample (note that no effort has been made to address any possible Rails reserved words issue in the sample). class File < ActiveRecord::Base has_many :records, :dependent => :destroy accepts_nested_attributes_for :records, :allow_destroy => true end class Record < ActiveRecord::Base belongs_to :file has_many :users, :dependent => :destroy accepts_nested_attributes_for :users, :allow_destroy => true end class User < ActiveRecord::Base belongs_to :record end Upon entering records, the database contents will appear as such. My issue is that if there are a lot of Files for the same Record, there will be duplicate record names. This will also be true if there will be multiple Records for the same user in the the Users table. I was wondering if there is a better way than this so as to have one or more files point to a single Record entry and one or more Records will point to a single User. BTW, the File names are unique. Files table: id name 1 name1 2 name2 3 name3 4 name4 Records table: id file_id record_name record_type 1 1 ForDaisy1 ... 2 2 ForDonald1 ... 3 3 ForDonald2 ... 4 4 ForDaisy1 ... Users table: id record_id username 1 1 Daisy 2 2 Donald 3 3 Donald 4 4 Daisy Is there any way to optimize the database to prevent duplication of entries, or this should really the correct and proper behavior. I spread out the database into different tables to be able to easily add new columns in the future.

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• SQLce DAL Linq to Sql or EntityFramework

  - by bretddog

  Hi, I'm learning databases, using SqlCe, and need business object to database mapping. Currently I try to decide if to use Linq to Sql, or EntityFramework. (I understand a bit L2S, but haven't familiarized with EF yet) The program will only be debeloped and used by myself, so I have good control of the priorities: I don't need to consider potential change of database type or data storage type, as I'm quite certain SQLce will stay sufficient. I DO expect continued development and changes to the data scheme while the program is in active use; change business object properties (Hence database columns), and possibly overall table scheme. So old data must be transported to new scheme. I also want to keep a decent degree of layer separation DAL/BLL, although this may not be necessary, it is good for me to learn these principles. My question is: With these priorities, would I have any benefit by choosing either Linq2Sql vs. EntityFramwork? (and please explain why) Btw, the project involves very simple table scheme with only 4-5 tables and very simple relations. Thanks!

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• JPA joined column allow every value...

  - by Fabio Beoni

  I'm testing JPA, in a simple case File/FileVersions tables (Master/Details), with OneToMany relation, I have this problem: in FileVersions table, the field "file_id" (responsable for the relation with File table) accepts every values, not only values from File table. How can I use the JPA mapping to limit the input in FileVersion.file_id only for values existing in File.id? My class are File and FileVersion: FILE CLASS @Id @GeneratedValue(strategy = GenerationType.IDENTITY) @Column(name="FILE_ID") private Long id; @Column(name="NAME", nullable = false, length = 30) private String name; //RELATIONS ------------------------------------------- @OneToMany(mappedBy="file", fetch=FetchType.EAGER) private Collection <FileVersion> fileVersionsList; //----------------------------------------------------- FILEVERSION CLASS @Id @GeneratedValue(strategy = GenerationType.IDENTITY) @Column(name="VERSION_ID") private Long id; @Column(name="FILENAME", nullable = false, length = 255) private String fileName; @Column(name="NOTES", nullable = false, length = 200) private String notes; //RELATIONS ------------------------------------------- @ManyToOne(fetch=FetchType.EAGER) @JoinColumn(name="FILE_ID", referencedColumnName="FILE_ID", nullable=false) private File file; //----------------------------------------------------- and this is the FILEVERSION TABLE CREATE TABLE `JPA-Support`.`FILEVERSION` ( `VERSION_ID` bigint(20) NOT NULL AUTO_INCREMENT, `FILENAME` varchar(255) NOT NULL, `NOTES` varchar(200) NOT NULL, `FILE_ID` bigint(20) NOT NULL, PRIMARY KEY (`VERSION_ID`), KEY `FK_FILEVERSION_FILE_ID` (`FILE_ID`) ) ENGINE=MyISAM AUTO_INCREMENT=4 DEFAULT CHARSET=latin1

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• How to publish internal data to the internet - as simple as possible

  - by mlarsen

  We have a .net 2-tier application where a desktop program is talking to a database. We support MS SQL Server 2000, 2005, 2008 and Oracle 9, 10 and 11. The application is sold, not as shrink-wrap, but pretty close. It is quite important for us that the installation and configuration is as easy as possible as installation instructions are usually supplied in written form to the customers internal IT-department. Our application is usually not seen as mission critical for the IT-department, so we need to keep their work down to a minimum. Now we are starting to get wishes for a web application build on top of the same data. The web application will be hosted by us and delivered as a SaaS application. Now the challenge is how to move data back and forth between the web application and the customers internal database. as I see it we have some requirements: We must be ready to handle the situation where the customers database is not accessible from the DMZ. I guess the easiest solution is that all communication is initiated from inside the customers lan. As little firewall configuration as possible. The best is if we can run without any special configuration as long as outgoing traffic from the customers lan are not blocked. If we need something changed in the firewall, we must be able to document that the change is secure. It doesn't have to be real time. Moving data in batches every ten minutes or so is OK. Data moves both ways, but not the same tables, so we don't have to support merges. It would be nice if we don't have to roll our own framework completely. Looking forward to hear your suggestions.

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• Help Me With This Access Query

  - by yae

  I have 2 tables: "products" and "pieces" PRODUCTS idProd product price PIECES id idProdMain idProdChild quant idProdMain and idProdChild are related with the table: "products". Other considerations is that 1 product can have some pieces and 1 product can be a piece. Price product equal a sum of quantity * price of all their pieces. "Products" table contains all products (p EXAMPLE: TABLE PRODUCTS (idProd - product - price) 1 - Computer - 300€ 2 - Hard Disk - 100€ 3 - Memory - 50€ 4 - Main Board - 100€ 5 - Software - 50€ 6 - CDroms 100 un. - 30€ TABLE PIECES (id - idProdMain - idProdChild - Quant.) 1 - 1 - 2 - 1 2 - 1 - 3 - 2 3 - 1 - 4 - 1 WHAT I NEED? I need update the price of the main product when the price of the product child (piece) is changed. Following the previous example, if I change the price of this product "memory" (is a piece too) to 60€, then product "Computer" will must change his price to 320€ How I can do it using queries? Already I have tried this to obatin the price of the main product, but not runs. This query not returns any value: SELECT Sum(products.price*pieces.quant) AS Expr1 FROM products LEFT JOIN pieces ON (products.idProd = pieces.idProdChild) AND (products.idProd = pieces.idProdChild) AND (products.idProd = pieces.idProdMain) WHERE (((pieces.idProdMain)=5)); MORE INFO The table "products" contains all the products to sell that it is in the shop. The table "pieces" is to take a control of the compound products. To know those who are the products children. For example of compound product: computers. This product is composed by other products (motherboard, hard disk, memory, cpu, etc.)

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• Are document-oriented databases any more suitable than relational ones for persisting objects?

  - by Owen Fraser-Green

  In terms of database usage, the last decade was the age of the ORM with hundreds competing to persist our object graphs in plain old-fashioned RMDBS. Now we seem to be witnessing the coming of age of document-oriented databases. These databases are highly optimized for schema-free documents but are also very attractive for their ability to scale out and query a cluster in parallel. Document-oriented databases also hold a couple of advantages over RDBMS's for persisting data models in object-oriented designs. As the tables are schema-free, one can store objects belonging to different classes in an inheritance hierarchy side-by-side. Also, as the domain model changes, so long as the code can cope with getting back objects from an old version of the domain classes, one can avoid having to migrate the whole database at every change. On the other hand, the performance benefits of document-oriented databases mainly appear to come about when storing deeper documents. In object-oriented terms, classes which are composed of other classes, for example, a blog post and its comments. In most of the examples of this I can come up with though, such as the blog one, the gain in read access would appear to be offset by the penalty in having to write the whole blog post "document" every time a new comment is added. It looks to me as though document-oriented databases can bring significant benefits to object-oriented systems if one takes extreme care to organize the objects in deep graphs optimized for the way the data will be read and written but this means knowing the use cases up front. In the real world, we often don't know until we actually have a live implementation we can profile. So is the case of relational vs. document-oriented databases one of swings and roundabouts? I'm interested in people's opinions and advice, in particular if anyone has built any significant applications on a document-oriented database.

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