Entity Framework 6 Refresher: Seed Data

“Seed Data” is data that is inserted into the database when migrations are run. Generally, this would be relatively static look-up data such as States or OrderStatuses. but it can be anything you want.

Using the example of Person in the previous post, we can use the seed functionality to created some records. To do this, open Configuration.cs in the Migrations folder. There will be Seed method.

protected override void Seed(LearnMappings.LearnMappingsContext context)
{
    //  This method will be called after migrating to the latest version.


    //  You can use the DbSet<T>.AddOrUpdate() helper extension method 

    //  to avoid creating duplicate seed data.

    var p1 = new Person() {FirstName = "John", LastName = "Smith", PersonId = 1};
    var p2 = new Person() {FirstName = "Jane", LastName = "Doe", PersonId = 2};
    context.People.AddOrUpdate(p1);
    context.People.AddOrUpdate(p2);
}

As noted in the comments the ` DbSet.AddOrUpdate()` will insert new data or update existing items with any changes.

PersonId, which is an identity column, can be ignored or set explicitly.

The seed method can be run via update-database in the PMC even without a pending migraiton.