ASP.NET 4.0 and the Entity Framework 4 - Part 2: Perform CRUD Operations Using the Entity Framework 4
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by Vince Varallo
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Step 1: Modify the Database Generated in Part 1

Part 1 of this article demonstrated how to create two entities using the Entity Framework 4.  The two entities are UserAccount and Address.  Each entity had an Id field defined as the primary key and various fields specific to the entity.  The one thing I forgot to show you in the first article was how to tell the Entity Framework to define the Id field as an Identity field.

1.    Launch Visual Studio and open the OrderSystem project.

2.    Double click on the OrderDB.edmx file in the Solution Explorer to view the Entity Framework designer.

3.    Click on the Id field in the UserAccount entity and view its properties.

4.    To define a field as an Identity field you need to change the StoreGeneratedPattern property to Identity.  Do the same for the Id field in the Addresses entity.

Figure 2

5.    Now that the Entity Model is updated, you need to update the database.  Right click on the Designer and select Generate Database From Model.  This will bring up the Generate Database Wizard.  The DDL to create the two tables with the Identity field will be automatically generated.  Click the Finish button to create the script.  You'll get the following message warning you that you are going to overwrite the script that already exists.  Click the Yes button to generate the script.

Figure 3

6.    The OrderDB.edmx.sql file will be overwritten and should open in Visual Studio.  You now need to execute the sql file against the database.  To do this simply right click anywhere in the file and select Execute SQL from the pop-up menu.

Figure 4

You'll be prompted to connect to the database.  Once you log in the script will execute.


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User Comments

Title: oussama   
Name: skksll
Date: 2012-11-26 9:58:51 AM
Comment:
great
Title: Very Good Article   
Name: cafeasp
Date: 2012-06-25 11:07:38 AM
Comment:
I just try the 'Update' code and it works perfect!

Thanks for sharing this info.
Title: Help there are erros in executing the sql file   
Name: Silver
Date: 2012-01-27 12:42:52 AM
Comment:
Msg 911, Level 16, State 1, Line 1
Database 'OrderSystem' does not exist. Make sure that the name is entered correctly.
Msg 262, Level 14, State 1, Line 17
CREATE TABLE permission denied in database 'master'.
Msg 262, Level 14, State 1, Line 3
CREATE TABLE permission denied in database 'master'.
Msg 4902, Level 16, State 1, Line 7
Cannot find the object "dbo.UserAccounts" because it does not exist or you do not have permissions.
Msg 4902, Level 16, State 1, Line 3
Cannot find the object "dbo.Addresses" because it does not exist or you do not have permissions.
Msg 4902, Level 16, State 1, Line 7
Cannot find the object "dbo.Addresses" because it does not exist or you do not have permissions.
Title: images   
Name: k k h
Date: 2011-12-09 2:25:39 PM
Comment:
Images are broken.
Title: CRUD operation   
Name: Suvashis
Date: 2011-04-07 6:45:55 AM
Comment:
Lots of thanks for the EF 4.0 CRUD Operation understanding
Title: You are the man   
Name: LukTar
Date: 2011-02-07 5:19:08 PM
Comment:
Big respect for YOU. Great article which helped me a lot.
Title: Great Work   
Name: Mayank
Date: 2010-10-29 4:26:15 AM
Comment:
It very helpful article to understand the initial CRUD operations using Entity Framework 4

Thanks a lot
Title: trusted   
Name: david zing
Date: 2010-07-05 7:35:59 PM
Comment:
ent:
I can´t use the lines the code below to update the entity:

db.UserAccounts.Attach(userAccount);
db.ObjectStateManager.ChangeObjectState(userAccount, System.Data.EntityState.Modified);

on the first line I get the message: Attach is not a member of System.Data.Objects.ObjectQuery(Of...)

What´s wrong ?
Title: Mr   
Name: David Zing
Date: 2010-06-09 6:52:52 AM
Comment:
I can´t use the lines the code below to update the entity:

db.UserAccounts.Attach(userAccount);
db.ObjectStateManager.ChangeObjectState(userAccount, System.Data.EntityState.Modified);

on the first line I get the message: Attach is not a member of System.Data.Objects.ObjectQuery(Of...)

What´s wrong ?
Title: N-Tier?   
Name: V. Jenks
Date: 2010-05-10 10:43:30 AM
Comment:
I'd love to see an article this straightforward and approachable in an n-tier tutorial? The EF seems very simple until you try and separate concerns. What if I'd like to store all of my business logic and data access in a separate class library project?
Title: Very good intro   
Name: Marshall
Date: 2010-05-05 2:23:05 PM
Comment:
Great intro to EF and made very simple to understand.
Title: Thanks   
Name: Soyka
Date: 2010-05-05 1:30:11 AM
Comment:
I'm coding just for fun and sometimes I don't know where to start with a new thing. Your articles put me on the right track...Thanks
Title: Far Too Good   
Name: Sreedevi
Date: 2010-03-31 7:14:48 AM
Comment:
This is a very nice article. Its seems like a cake walk creating applications using VS2010. Hope we get to work on VS 2010 very soon.

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