Building and Using a LINQ for SQL Class Library with ASP.NET 2.0
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by Scott Guthrie
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Step 3: Quickly creating a Northwind data model

One of the really easy ways to quickly define your data model classes is to open up the Server Explorer tab within VS 2005 and connect to your database.  You can then drill into the Tables and Views within your database and drag/drop them from the server explorer onto the DLINQ designer surface to automatically create data models for them.  For example, if I dragged/dropped the Suppliers, Customers, Orders, Order Details, and Products tables onto the designer surface, by default I would get a data model that looks like this:

Figure 4

Note how the DLINQ designer automatically sets up default associations between the different entities based on the Primary Key/Foreign Key relationships in the database.  These will automatically cause properties to be created on the various data classes so that we can perform rich querying and/or easily traverse between them.  For example, if I had a "Customer" instance above I could simply access the "Customer.Orders" property to get a collection of all of the Customer's orders in the database.

If you want, you can add, delete or alter these associations by simply clicking on the association links in the designer and then use the property grid to change its settings.  For example, if I wanted to modify the "Order Details" associations above to be named "OrderDetails," I would click on the association line in the designer and change it via the property grid below. Or because it supports inline editing for the name, I could also just click on the name in the designer and rename it in place.  See Figure 5 below for both options.


Figure 5

Additionally, I could use the designer to easily rename the entities and/or rename/remove/add properties to them.  Once we are done defining your data models, we will just save the file.  The designer will then automatically generate a .cs or .vb file containing the LINQ data class definitions.  This is saved in a nested file underneath the Northwind.dlinq item in the solution explorer.

Figure 6

The LINQ data model classes created are defined as "partial" classes" which means we will be able to go in later and add entity and property validation rules that enforce our business logic, as well as add any additional properties or helper methods we want to the classes.

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User Comments

Title: ras   
Name: rasd
Date: 2012-05-05 4:29:50 AM
Title: How to integrate with XLINQ in eixsting applications   
Name: Senthil
Date: 2008-12-17 12:20:06 AM
How to integrate with XLINQ in eixsting applications?
Title: nice   
Name: john
Date: 2006-09-20 5:21:27 AM
nice.. that give me a point

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