How to make fields unique in C# using EF Core?

Question

I want to make a field unique in EF Core and I'm using .NET 5. I can't use the [Index(IsUnique = true)] attribute because if I try, I get an error. Maybe It's a part of EF but not EF Core.

How can I achieve this?

I've done several searches but I didn't find any suitable answer.

Answer 1

You can do like this.

class MyContext: DbContext {
  public DbSet<Test> Tests { get; set; }

  protected override void OnModelCreating(ModelBuilder modelBuilder) {
    modelBuilder.Entity<Test>()
      .HasIndex(x => x.ColumnName)
      .IsUnique();
  }
}