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Constraint [message #591901] Thu, 01 August 2013 06:03 Go to next message
Messages: 61
Registered: July 2012
mysql> use new;
Database changed
mysql> show tables;
| Tables_in_new |
| books         |
| dvds          |
| employee      |
| orders        |
| penalties     |
| professor     |
| studios       |
| topic         |
| users_profile |
9 rows in set (0.00 sec)

mysql> show create table books;
| Table | Create Table
| books | CREATE TABLE `books` (
  `BookID` smallint(6) NOT NULL,
  `BookName` varchar(40) NOT NULL,
  `InStock` smallint(6) NOT NULL,
1 row in set (0.00 sec)

mysql> drop table books;
ERROR 1217 (23000): Cannot delete or update a parent row: a foreign key constraint fails

As i am new to MYSQL , i dont know how to drop the table which contains Primary key column and it was an dependent object to the other table. When i use to drop the table, i m getting error as i showed above.

Also In the above table BOOKS, i want to know which table references the BOOKS table.
kindly suggest me an answer.
Re: Constraint [message #591902 is a reply to message #591901] Thu, 01 August 2013 06:11 Go to previous message
Messages: 21268
Registered: June 2005
Location: Croatia, Europe
Senior Member
Account Moderator
I don't use MySQL. However: as you saw, you can't drop a table whose primary key is referenced by a foreign key.

Google says that this page (among many of them) contains information about finding foreign key constraints. Have a look.
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