Entity Framework Migrations seeds duplicate rows - entity-framework

Question

I've got two classes
public class Category
{
public int Id { get; set; }
public string Name { get; set; }
}
public class Item
{
public int Id { get; set; }
public sting Name { get; set; }
public Category Category { get; set; }
}
I have EF Migrations and the following seed:
var instockCategory = new Category() { Name = "InStock" };
var outofStockCategory = new Category() { Name = "OutOfStock" };
context.Items.AddOrUpdate(
d => d.Name,
new Item() { Name = "Item1", Category = instockCategory },
new Item() { Name = "Item2", Category = outofStockCategory },
new Item() { Name = "Item3", Category = outofStockCategory }
);
The line "d => d.Name" makes sure that based on the name of the item, there won't be duplicate records when I reseed the database.
However, the first time I execute this, two categories are created with id 1 and 2. But the second time I run this, 3 new categories are created!
Can I fix this without manually adding every single category first?

Answer 1

You have to use AddOrUpdate for your categories too.
var instockCategory = default(Category);
var outofStockCategory = default(Category);
context.Set<Category>().AddOrUpdate(
c => c.Name,
instockCategory = new Category() { Name = "InStock" },
outofStockCategory = new Category() { Name = "OutOfStock" }
);
context.Items.AddOrUpdate(
d => d.Name,
new Item() { Name = "Item1", Category = instockCategory },
new Item() { Name = "Item2", Category = outofStockCategory },
new Item() { Name = "Item3", Category = outofStockCategory }
);
An explicit DbSet on your Context class is not necessary.
public class Context : DbContext
{
public DbSet<Item> Items { get; set; }
}