# IT:AD:Code First:FluentAPI:Properties #



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## Examples: Properties ##

The following just specify contraints on size, key, etc.

For Relationship Contraints, see [[IT/AD/Code First/FluentAPI/Relationships/]]
 

#### Primary Key ####
It's done automatically if you the fieldname is called `Id` or `TheEntitityId`, but if you can't use that field name:

    modelBuilder.Entity<Manager>()
      .HasKey(ma => ma.ManagerCode);

#### Composite Keys ####
Use an anonymous object:

    modelBuilder.Entity<Department>()
      .HasKey(t => new { t.DepartmentID, t.Name });

#### MaxLength ####

    modelBuilder.Entity<Manager>().Property(ma => ma.Name)
      .HasMaxLength(20);

#### Required ####

    modelBuilder.Entity<Department>().Property(dp => dp.Name)
      .IsRequired();


#### Ignore ####
You can ignore calculated columns:

    modelBuilder.Entity<Department>().Ignore(t => t.Budget);


#### Mapping to a different Column ####

    modelBuilder.Entity<Department>().Property(t => t.Name)
      .HasColumnName("DepartmentName");

#### Reference: Property Related FluentAPI ####

* [http://msdn.microsoft.com/en-us/library/hh295847(v=vs.103).aspx](http://msdn.microsoft.com/en-us/library/hh295847(v=vs.103).aspx)