ASP. net mvc + LINQ develop a book sales site (6): create a data layer

1. we store the data required by our system under the model. First, we create a database's LINQ to SQL class

2. Select all tables to the design view.

3. Create a bookshopdbdatacontext distribution class. Here we will write some methods to interact with the Controller in the logic layer.

Using System;
Using System. Data;
Using System. configuration;
Using System. LINQ;
Using System. xml. LINQ;
Using System. Collections. Generic;

Namespace Bookshop. Models
{
Public   Partial   Class Bookshopdbdatacontext
{
// Return all categories
Public List < Category > Getallcategory ()
{
Return Categories. tolist ();
}

// Add Category
Public void addcategory (category C)
{< br> This . categories. insertonsubmit (c);
This . submitchanges ();
}

// edit Category
Public void editcategory (category C)
{< br> This . updatecategory (c);
This . submitchanges ();
}

Public category getcategory ( int ID)
{< br> return categories. single (C => C. categoryid = ID );
}

//Delete category
Public BoolDelcategory (IntID)
{

// Check if has used
If (Books. Any (B => B. bookcategoryid = ID ))
{
Return   False ;
}
Else
{
CATEGORY delcategory =   This . Categories. Single (C => C. categoryid = ID );
This . Categories. deleteonsubmit (delcategory );
This . Submitchanges ();
Return   True ;
}
}
}
}