EF Core 2.1 seeding data primary key-CodePudding

I have just run into an issue, reminiscent of chicken and egg situation.

I'm trying to seed data in EF 2.1.3. I have a class called "Sample".

public class Sample
    {
        public long Id { get; set; }
        public string Name { get; set; }
        public string Description { get; set; }
        public bool IsActive { get; set; }
        public bool IsVisible { get; set; }
    }

I have the following seed method:

builder.HasData(
                new Sample {Id=1, IsActive = true, IsVisible = true, Name = "Test 1" },
                new Sample { Id = 2, IsActive = true, IsVisible = true, Name = "Test 2" },
                new Sample { Id = 3, IsActive = true, IsVisible = true, Name = "Test 3" }
                );

Now, this seems to have worked ok the first time I have generated the migrations

Now, however, every time I run Add-Migration command I get this error:

The seed entity for entity type 'Sample' cannot be added because another seed entity with the same key value for {'Id'} has already been added. Consider using 'DbContextOptionsBuilder.EnableSensitiveDataLogging' to see the conflicting key values.

Getting rid of Id values from seed data - results in this error:

The seed entity for entity type 'Sample' cannot be added because there was no value provided for the required property 'Id'.

CodePudding user response：

EF core requires keys to be added to the pocos because it needs to know which is the primary key. You can try adding data attributes like your [Key] and [Required] to your class properties

Here is a write up on data attributes

You also don’t typically have to add ID if your table is auto incrementing assuming your using a relational database

CodePudding user response：

This is the Ids has been previously added. You are inserting duplicate key values.