EF Core cannot insert the value null into column with default value

Question

I have entity

public class Realtor
{
    [Key]
    public int Id { get; set; }

    [DatabaseGenerated(DatabaseGeneratedOption.Identity)]
    public Guid Guid { get; set; }

    public string FirstName { get; set; }
    public string LastName { get; set; }

    [DatabaseGenerated(DatabaseGeneratedOption.Identity)]
    public DateTime Registration { get; set; }

    [ForeignKey("Id")]
    public int SubdivId { get; set; }
    public Subdiv Subdiv { get; set; }
}

and context with OnModelCreating method

modelBuilder.Entity<Realtor>(real => {
            real.Property<Guid>(p => p.Guid)
            .HasDefaultValueSql("newsequentialid()");

            real.Property<DateTime>(p => p.Registration)
            .HasDefaultValueSql("getdate()");

            real.HasOne(r => r.Subdiv)
            .WithMany(s => s.Realtors)
            .HasForeignKey(r => r.SubdivId);
        });

I set default value for property Registration, but when I do an insert, I get Exception: cannot insert the value null into column Registration.

Why do you have a DateTime as Identity? That shouldn't be there, and why do you have both a Guid and an Id, and trying to make both the identity? — Dispersia, Nov 01 '16 at 16:21
How can you be setting a `null` value for a non-nullable `DateTime` property? More likely, it is the `[DatabaseGenerated(DatabasegeneratedOption.Identity)]` attribute. I would imagine that `Identity` isn't defined for `DateTime` values, but only `int`. — krillgar, Nov 01 '16 at 16:22

Matthias Burger · Accepted Answer · 2016-11-01T16:49:42.717

First of all, remove the [DatabaseGenerated(DatabaseGeneratedOption.Identity)] for Restration. This could be the cause for your exception. If you don't want to make it nullable and want to set the value with your entity you could also:

public DateTime Restration { get; set; } = DateTime.Now;

Should work (I ain't got a VS 2015 here, so you have to test. Otherwise set the value for Restration in constructor.)

update: and remove at least this line

real.Property<DateTime>(p => p.Registration)
        .HasDefaultValueSql("getdate()");

score 2 · Answer 2 · edited Nov 01 '16 at 18:29

2

Remove

[DatabaseGenerated(DatabaseGeneratedOption.Identity)]

Add a constructor in your Realtor class.

public Realtor()
{
  this.Guid = Guid.NewGuid();
  this.Restration = DateTime.Now;
}

And remove this from OnModelCreating

real.Property<Guid>(p => p.Guid).HasDefaultValueSql("newsequentialid()");
real.Property<DateTime>(p => p.Restration).HasDefaultValueSql("getdate()");

edited Nov 01 '16 at 18:29

Matthias Burger

5,549
7
49
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answered Nov 01 '16 at 16:35

Angel Pincay

21
3

It works! But I think that it is dubious decision. After all, it should work in the EF. – Dmitriy Gavrilenko Nov 01 '16 at 16:57
@Matthias Burger I'm sorry. I did not see your answer – Dmitriy Gavrilenko Nov 01 '16 at 17:14

EF Core cannot insert the value null into column with default value

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