Entity Framework make set of columns unique

Admin 1
Viewed 72

Say I have the following table with the following data

enter image description here

And I want to insert a new record of {Paul, 30, M}.

I want the DBContext to reject this. Essentially what I want is the Name, Age and Gender to be unique in combo. No record can have the same name, age or gender.

public class MyModel
{
  public int ID { get; set; }
  public string Name { get; set; }
  public int Age { get; set; }
  public string Gender { get; set; }
}

My Context is setup to just have a key

public class MyContext : DbContext
{
   public DbSet<MyModel> MyModels { get; set; }

   public override void OnModelCreating(ModelBuilder modelBuilder)
   {
      modelBuilder.Entity<MyModel>()
         .HasKey(o => new { o.Id });
   }
}
entity-framework sql-server c#
1 Answers

More likely, you'll need either to have unique index or an alternate key.

With an index:

public class MyContext : DbContext
{
   public DbSet<MyModel> MyModels { get; set; }

   public override void OnModelCreating(ModelBuilder modelBuilder)
   {
      modelBuilder.Entity<MyModel>()
         .HasKey(o => new { o.Id });

      modelBuilder.Entity<MyModel>()
         .HasIndex(p => new {p.Name, p.Gender, p.Age}).IsUnique();
   }
}

With an alternate key:

public class MyContext : DbContext
{
   public DbSet<MyModel> MyModels { get; set; }

   public override void OnModelCreating(ModelBuilder modelBuilder)
   {
      modelBuilder.Entity<MyModel>()
         .HasKey(o => new { o.Id });

      modelBuilder.Entity<MyModel>()
         .HasAlternateKey(p => new {p.Name, p.Gender, p.Age});
   }
}
user_47271320
Related