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Use the Unique constraint dialog to define a unique constraint for a specified table. Unique constraints ensure that the data contained in a column, or a group of columns, is unique among all the rows in the table.
The Unique constraint dialog organizes the development of a unique constraint through the following dialog tabs: General and Definition. The SQL tab displays the SQL code generated by dialog selections.
Use the fields in the General tab to identify the unique constraint:
Click the Definition tab to continue.
Use the fields in the Definition tab to define the unique constraint:
Click the SQL tab to continue.
Your entries in the Unique constraint dialog generate a SQL command (see an example below). Use the SQL tab for review; revisit or switch tabs to make any changes to the SQL command.
The following is an example of the sql command generated by user selections in the Unique constraint dialog:
The example shown demonstrates creating a unique constraint named name_con on the name column of the distributors table.