in entity framework code first, how to use KeyAttribute on multiple columns

Question

I'm creating a POCO model to use with entity framework code first CTP5. I'm using the decoration to make a property map to a PK column. But how can I define a PK on more then one column, and specifically, how can I control order of the columns in the index? Is it a result of the order of properties in the class?

Thanks!

Answer 1

You can specify the column order in the attributes, for instance:

public class MyEntity {     [Key, Column(Order=0)]     public int MyFirstKeyProperty { get; set; }      [Key, Column(Order=1)]     public int MySecondKeyProperty { get; set; }      [Key, Column(Order=2)]     public string MyThirdKeyProperty { get; set; }      // other properties } 

If you are using the Find method of a DbSet you must take this order for the key parameters into account.