Is it possible to add CHECK constraint with fluent API in EF7?

Question

Is it possible to add CHECK constraint with fluent API in Entity Framework 7?

I need to acheive something like this:

...
ADD CONSTRAINT CK_SomeTable_         


        

Answer 1

Lukas Kabrt is still valid in 2019 so I had to create a special migration that I will include constraint and its drop:

        protected override void Up(MigrationBuilder migrationBuilder)
        {
            migrationBuilder.Sql(@"
alter table AdminObjectReview add CONSTRAINT CK_AdminObjectReview_OnlyOneType CHECK 
( 
      (CASE WHEN AnswerId IS NULL THEN 0 ELSE 1 END)
    + (CASE WHEN QuestionId IS NULL THEN 0 ELSE 1 END)
    + (CASE WHEN CommentId IS NULL THEN 0 ELSE 1 END)
    + (CASE WHEN UserId IS NULL THEN 0 ELSE 1 END)
    + (CASE WHEN TagId IS NULL THEN 0 ELSE 1 END)
     = 1 )
");
        }

        protected override void Down(MigrationBuilder migrationBuilder)
        {
            migrationBuilder.Sql("alter table AdminObjectReview  drop CONSTRAINT CK_AdminObjectReview_OnlyOneType");
        }

Answer 2

As of EF 7.0.0-rc1, it isn't possible with the fluent API.

You can define the constraint manually in the migration

migrationBuilder.Sql("ALTER TABLE SomeTable ADD CONSTRAINT CK_SomeTable_SomeColumn CHECK (SomeColumn >= X);");

Answer 3

As of EF Core 3.0, you can use

protected override void OnModelCreating(ModelBuilder modelBuilder)
{
    modelBuilder.Entity<SomeTable>(entity =>
        entity.HasCheckConstraint("CK_SomeTable_SomeColumn", "[SomeColumn] >= X");
}