The entity type 'Employee' requires a primary key to be defined. If you intended to use a keyless entity type, call 'HasNoKey' in 'OnModelCreating'. code example

Example: The entity type 'IdentityUserLogin' requires a primary key to be defined. If you intended to use a keyless entity type call 'HasNoKey()'

protected override void OnModelCreating(ModelBuilder modelBuilder)
{
  base.OnModelCreating(modelBuilder);
}