Code-First Approach
An alternative to introspecting the model from the provider is to handwrite your model classes. This is the code-first approach to Entity Framework, which gives you greater control over the exact data model you use in your application.
Install Entity Framework
Install Entity Framework or add references to the required assemblies for your chosen version of Entity Framework. See
Using EF 6 for using Entity Framework 6. See
Installed Assemblies for more information about all assemblies shipped with the provider.
Register the Provider
Add the connection string to App.Config or Web.config. The connectionStrings node is often located directly below the configSection node in the root configuration node.
<configuration>
...
<connectionStrings>
<add name="CompositeContext" connectionString="Host=myHost;Domain=myDomain;DataSource=myDataSource;User=myUser;Password=myPassword" providerName="System.Data.CompositeClient" />
</connectionStrings>
...
</configuration>
Create the Context Class
Start by creating the CompositeContext class. This is the base object that extends DbContext and exposes the DbSet properties that represent the tables in the data source. Next, override some of the default functionality of the DbContext class by overriding the OnModelCreating method. You can find a description of these properties in the code below:
using System.Data.Entity;
using System.Data.Entity.Infrastructure;
using System.Data.Entity.ModelConfiguration.Conventions;
class CompositeContext : DbContext {
public CompositeContext() { }
public DbSet<Products> Products { set; get; }
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
// To remove the requests to the Migration History table
Database.SetInitializer<CompositeContext>(null);
// To remove the plural names
modelBuilder.Conventions.Remove<PluralizingTableNameConvention>();
//For versions of EF before 6.0, uncomment the following line to remove calls to EdmTable, a metadata table
//modelBuilder.Conventions.Remove<IncludeMetadataConvention>();
}
}
Create the Table Models
Finally, define a class for each table that was defined in the DbSet properties of the context class. The table classes should have a list of properties that correspond to each field of that table. A corresponding map class must be defined to configure attributes for each property in the table class.
using System.Data.Entity.ModelConfiguration;
using System.ComponentModel.DataAnnotations.Schema; //EF 6 and later
//using System.ComponentModel.DataAnnotations //For versions of EF before 6
[System.ComponentModel.DataAnnotations.Schema.Table("Products")]
public class Products {
[System.ComponentModel.DataAnnotations.Key]
public System.String Id { get; set; }
public System.String ProductName { get; set; }
}
Perform LINQ Commands in Your Code
You are now ready to start using LINQ in your code. Be sure to declare "using System.Linq" in your file.
CompositeContext ents = new CompositeContext();
var ProductsQuery = from Products in ents.Products
orderby Products.ProductName
select Products;