ASA SQL User's Guide
Working with Database Objects
Working with tables
Managing primary keys
In Sybase Central, the primary key of a table appears in several places:
On the Columns tab of the table's property sheet.
On the Columns tab in the right pane when a table is selected in the left pane.
The lists in both the table property sheet and on the Columns tab display the primary key columns (along with the non-key columns) in the order that they were created in the database. This may differ from the actual ordering of columns in the primary key.
To create and edit the primary key (Sybase Central)
Open the Tables folder.
In the left pane, select the desired table.
In the right pane, click the Columns tab.
Change the primary as desired.
To make a column a primary key column, place a checkmark in the checkbox beside the column name. Clear the checkbox to remote the column from the primary key.