Adding constraint on an existing table with CHECK

Question

Can anyone have a look at my SQL statement and tell me what is wrong with it. I keep getting error when I tried to add a new constraint on an existing table.

Error report:
SQL Error: ORA-01735: invalid ALTER TABLE option
01735. 00000 -  "invalid ALTER TABLE option"
*Cause:    
*Action:

Answer 1

You need parentheses around the entire condition for check :

alter table seat 
    add constraint check_seats
        CHECK ((BLOCKNO = 'FRONT' AND ROWNO NOT LIKE '%[^A-J]%'  AND SEATNO <=40) OR 
               (BLOCKNO = 'MIDDLE' AND ROWNO NOT LIKE '%[^A-L]%' AND SEATNO <=50) OR
               (BLOCKNO = 'BACK' AND ROWNO NOT LIKE '%[^A-N]%' AND SEATNO <=60)
              );

Answer 2

Add one more parenthesis for the check constraint.

     CHECK ((BLOCKNO = 'FRONT' AND ROWNO NOT LIKE '%[^A-J]%'  AND SEATNO <=40) OR 
            (BLOCKNO = 'MIDDLE' AND ROWNO NOT LIKE '%[^A-L]%' AND SEATNO <=50) OR
            (BLOCKNO = 'BACK' AND ROWNO NOT LIKE '%[^A-N]%' AND SEATNO <=60)
           );