Unique Constraint Tutorial

This tutorial will show you how to easily manage your Unique Constraints using Database Schema Designer.

• Add / Edit a Unique Constraint

  1. If Adding a new Unique Constraint:

     There are a number of methods to create a new Unique Constraint Constraint.   Choose the one you are most comfortable with:

     • Open Manage Unique Constraints screen and click the "Add" button.   See Manage Schema Objects Tutorial
     • Open the Table's properties, select the Constraints Tab, select the Unique Constraint option and then press the Add button.   See Edit Table Tutorial
     • Select "Insert -> Unique Constraint" from the main menu.
       
     • Right Click the Schema and select "New -> Unique Constraint -> Without selected Table" for a blank Unique Constraint.
       
     • Right Click the Schema and select "New -> Unique Constraint -> With selected Tables" for a Unique Constraint populated with the selected Tables.
       
     • Use the keyboard command "Ctrl+U" to add a blank Unique Constraint.
     • Use the keyboard command "Ctrl+Shift+U" to add a Unique Constraint populated with the selected Tables.

     If Editing an existing Unique Constraint:

     There are a number of methods to edit an existing Unique Constraint.   Choose the one you are most comfortable with:

     • Open Manage Unique Constraint screen and click the "Edit" button with the Unique Constraint selected.   See Manage Schema Objects Tutorial
     • Open the Table's properties, select the Constraints Tab, choose the Unique Constraint in the list then press the Edit button.   See Edit Table Tutorial
  2. Editing Unique Constraint Properties
     • Select the Parent Table.
       * The Parent Table lists will only be available when adding a new Unique Constraint to the Schema.   If you are editing an existing Unique Constraint, this lists will be disabled.
       
     • Setup the Unique Constraint Name as required.   See Object Names for more information.
     • Check at least one Column to make it a part of the Unique Constraint.
       
     • By default new Unique Constraint will be non-Clustered.   Select the Clustered if required.
       * Since a Table can have only 1 Clustered Index, you may be prompted to confirm this action before proceeding.
       
  3. Click OK to submit your changes.
     - OR -
     Click Cancel to discard your settings.
• Delete a Unique Constraint

  There are a number of methods to delete a Unique Constraint from the Schema.  Choose the one you are most comfortable with:

  • Open the Manage Unique Constraints screen and click Delete with the Unique Constraint selected.   See Manage Schema Objects Tutorial
  • Open the Table's properties, select the Unique Constraints Tab, choose the Unique Constraint in the list then press the Delete button.   See Edit Table Tutorial
  • Delete the Unique Constraint's Parent Table.   See Delete Table Tutorial