Entity Framework 7

Installation

PM> Install-Package EntityFramework.MicrosoftSqlServer -Pre

Creating Models

Models

public class Parent
{
  public int Id {get; set;}
  public string MasterName {get; set;}
  public ICollection<Child> {get; set;}
}

public class Child
{
  public int Id {get; set;}
  public string ChildName {get; set;}
}

Context

Then we start creating context. Create a **TestContext.cs** file in Models folder

public class TestContext : DbContext
{
  public DbSet<Parent> Parents {get; set;}
  public DbSet<Child> Children {get; set;}
}

Once we write **DbContext** in the class above it will be underlined and as a fix VS suggest to get EF7 Nuget package. Click this suggestion.

Configure Services

in **Startup.cs** under **ConfigureServices** section add the lines below

services.AddEntityFramework()
  .AddSqlServer()
  .AddDbContext<TestContext>();

• • TestContext** here is the one we defined in Context section

Configure Db Provider

in config.json add a new section named Data

"Data":{"TestContextConnection":"Server=SomeServer;
    Database=TestDb;
    Trusted_Connection=true;
    MultipleActiveResultSets=true;"}
    

in **TestContext.cs** file again

protected override void OnConfiguring(DbContext TestContext, OptionsBuilder optionsBuilder)
{
  var connString = Startup.Configuration["Data:TestContextConnection"]
  optionsBuilder.UseSqlServer(connString)
} 

Migrations

in **project.json** file add a dependency and add a line to **commands** section

  "EntityFramwework.Commands", "7.0.0-beta8"
 
  // in commands section 
  "ef":"EntityFramework.Commands"

Then in Command Prompt under the project folder <sxh> dnx ef migrations add InitialDatabase </pre>

• • ef** comes from project.json commands section and InitialDatabase is a name that we gave to this migration.

in **TestContext.cs** file

public class TestContext:DbContext
{
  //in constructor add the line below
  public TextContext() 
  {
    Database.EnsureCreated();
  }
}

This will create the database itself and if any migrations nedd to be executed it will execute them at the same time.

Seeding Data

Create **TestContextSeedData.cs** file in models folder

public class TestContextSeedData
{
  private TestContext = _context;
  public TestContextSeedData(TestContext context)
  {
    _context = context
  }
    public void EnsureSeedData()
    {
      if(! _context.Masters.Any())
      {
        var rMaster = new Master()
        {
          MasterName = "test",
          Children = new List<Child>()
          {
            new Child(){ ChildName = "TestChild"},
            new Child(){ ChildName = "TestChild2"}            
          }
        }
        _context.Masters.Add(rMaster);
        _context.Children.AddRange(rMaster.Children);
        _context.SaveChanges();
      }
    }
}

in startup.cs under Configure method

public void Configure(TestContextSeedData seeder)
{
 seeder.EnsureSeedData();
}

To use this class we need to register it in **startup.cs** file in **ConfigureServices**

services.AddTransient<TestContentSeedData>();

Options

 * AddTransient : only one instance supplied
 * AddSingleton : 
 * AddInstance : 
 * AddScoped : an instance will be created whenever needed

Stop and restart web server to activate services changes