Sets the predefined key groups to which a key belongs.
After you have assigned a key to one or more key groups, you can selectively enable or deactivate the key by enabling and disabling the key groups.
Adding lots of keys to a database table decreases performance. However, by making the keys members of predefined key groups you can define the keys and only enable them when they will be used. This improves performance. For information about how to enable or disable key groups, see How to: Enable or Disable a Key Group.
It is difficult to see an overview of the keys and tables that are affected when you enable or disable a key group. However, you can view which keys in a table belong to a key group. For information about how to view keys and key groups, see How to: View Keys and Key Groups.