These steps are part of the larger tasks of creating a table and altering a table. When you complete the steps for adding a primary key, return to either creating a table or altering a table.
To define a primary key:
You can define up to 64 columns to be primary key columns, and the sum of their lengths must not exceed 254.
Depending on the task that you were doing when you added the primary key, return to either creating a table or altering a table.