Entity Framework Code-First Migrations

Creating the Project

Create MVC project with Web API template
Create context class that inherits from DbContext
```
public class ServicesContext : DbContext
```

Enabling Code-First Migrations

Enable migrations from the Package-Manager console
```
PM> Enable-Migrations
```

Allow Code-First migrations in the generated Configuration.cs

public Configuration() 
{
    AutomaticMigrationsEnabled = true;
}

Build Models

Create basic C# objects

Any references to other objects should simply be that type, NOT an int ID type.
Good:

public Contact ServiceAgentContact { get; set; }

Bad:

public int ServiceAgentContactId { get; set; }

Migrating

Add entities to DbContext to be picked up on migration
```
public DbSet<Contact> Contacts { get; set; }
```
Update from Package-Manager console
```
PM> Update-Database
```

Basics Notes and Gotchas

References to other models default to many-to-one, and optional

Primitives default to non-nullable, as well. Use Nullable version to fix

...									
public int? OptionalValue { get; set; }
public DateTime? OptionalDate { get; set; }
...

Configuring

Use Attributes to enhance relationships

...
//Make Partner required for this model.
[Required]
public Partner Partner { get; set; }
public string CompanyName { get; set; }
...

Advanced

Modify relationships during migration run using Fluent API

public class ServicesContext : DbContext
{
	protected override void OnModelCreating(DbModelBuilder modelBuilder)
	{
	    modelBuilder.Entity<Partner>()
	        .HasOptional(p => p.Logo)
	        .WithOptionalDependent()
	        .Map(k => k.MapKey("Logo_Id"));
	    ...
	}
}

Will set Partner.Logo to be 1:1, but still optional