How Do I Retrieve the ID of a Newly Inserted Entity Using Entity Framework?

Accessing the ID of a Newly Inserted Entity in Entity Framework

A frequent task in Entity Framework involves obtaining the ID of an entity immediately after database insertion. Entity Framework typically employs automatic ID generation (like IDENTITY in SQL Server).

Standard Approach

Adding an entity to an ObjectSet and calling SaveChanges() automatically populates the ID property. Here's how:

<code class="language-csharp">using (var context = new MyContext())
{
    context.MyEntities.Add(myNewObject);
    context.SaveChanges();

    int id = myNewObject.Id; // The Id property is now populated
}</code>

Customizing ID Generation

Sometimes, you might need to control ID generation. Entity Framework's DatabaseGeneratedOption attribute offers various strategies.

Manual ID Assignment

For manually assigned IDs, use DatabaseGeneratedOption.None. This prevents Entity Framework from generating an ID; you must set it before adding the entity.

Computed IDs

If the ID is calculated (not from a table), use DatabaseGeneratedOption.Computed. Entity Framework retrieves the ID after the insert statement executes.

Summary

Retrieving the ID of a newly inserted entity in Entity Framework is generally simple. Automatic ID generation is the default, but customization options are available for specific scenarios.

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