Changing a primary key

These steps are part of the larger task of altering a table. When you complete these steps, return to altering a table.

To change an existing primary key:

1. Optional: On the Primary Key page, define additional columns as primary key columns.
   1. In the Available columns box, select an additional column or columns that you want to define as primary key columns. The columns that you select cannot allow null values.

      You can define up to 64 columns to be primary key columns, and the sum of their lengths must not exceed 254.

   2. Click on the > push button to move the selected column or columns to the Primary key columns box.

2. Optional: Remove some columns from the list of primary key columns:
   1. In the Primary key columns box, select the columns that you do not want to have as primary key columns.
   2. Click on the < push button to move them to the Available columns box.