-624 TABLE `table-name` ALREADY HAS A PRIMARY KEY OR UNIQUE CONSTRAINT WITH SPECIFIED COLUMNS AND PERIODS

Explanation
  An ALTER TABLE statement cannot be processed
for one of the following reasons:
The table already has a primary key.
The table has an existing unique constraint with
the same definition as the new key. (The existing set of columns and
periods is specified in the ALTER statement.)

System action
  The statement cannot be processed.

Programmer response
  Do not attempt to define a table with
more than one primary key, or a unique constraint that duplicates
the definition of an existing unique constraint.

SQLSTATE
42889 

-624 TABLE table-name ALREADY HAS A PRIMARY KEY OR UNIQUE CONSTRAINT WITH SPECIFIED COLUMNS AND PERIODS

Explanation

System action

Programmer response

SQLSTATE

-624 TABLE `table-name` ALREADY HAS A PRIMARY KEY OR UNIQUE CONSTRAINT WITH SPECIFIED COLUMNS AND PERIODS