All adding, altering, and deleting of column constraints in Sybase Central is carried out in the Constraints tab of the column properties sheet.
Displaying the property sheet for a column
Connect to the database.
Click the Tables folder for that database, and click the table holding the column you wish to change.
Double-click the Columns folder to open it, and double-click the column to display its property sheet.
For more information, see the Sybase Central online Help.
