Question

I use an abstract Entity class which contains a Guid:

public abstract class Entity
{
    public /*virtual*/ Guid Id { get; set; }
}

Suppose I also have a class like:

public class Post : Entity
{
    public String Title { get; set; }
    public String Content { get; set; }
    public DateTime Timestamp { get; set; }
}

How do I properly map Post class using xml-mapping? I’m asking about Id.

Answer 1

<id name="Id">
    <generator class="guid"/>
</id>

This will generate Guids on the client using the Guid.NewGuid() method.

Alternative generators are:

• guid.native – generates the Guids on the server side, e.g. using NEWID() on SQL server
• guid.comb – generates “sequential” Guids, which reduces index fragmentation.

I would recommend guid.comb for most applications that use Guid identifiers.