Cannot delete record from table which has Identity column

问题

I have a table which has the code as primary key instead of Id, When I call DeleteAsync method I get the exception Message = "Cannot update identity column 'Id'.".

[Table("Test")]

public class Test: FullAuditedEntity<int>

{

[DatabaseGenerated(DatabaseGeneratedOption.Identity)]
new public int Id { get; set; }
[Key]
[DatabaseGenerated(DatabaseGeneratedOption.None)]
public virtual int Code { get; set; }

public async Task DeleteTest(int code)
    {


        try
        {
            await _supplierRepository.DeleteAsync(p => p.Code== code);
        }
        catch (Exception ex)
        {

        }
    }

But If I remove Id column from the table, it works fine. I want both Id column and Code column as PK.

回答1:

What is happening is, by FullAuditedEntity<int> automatically creates an Id field of integer. You don't need to do this:

[DatabaseGenerated(DatabaseGeneratedOption.Identity)]
new public int Id { get; set; }

If you want to create a table with a composite key, go ahead and just add your Code Field without replicating the Id field. Then you will have no problems.

回答2:

It is recommended that We should use Id as PK and make other columns as a unique constraint. So if you use Id as PK, you won't face such issues.

来源：https://stackoverflow.com/questions/46173881/cannot-delete-record-from-table-which-has-identity-column