MySQL Bugs: #6202: DROP TABLE failure with misleading error message

Bug #6202	DROP TABLE failure with misleading error message
Submitted:	21 Oct 2004 20:57	Modified:	15 Feb 2005 17:27
Reporter:	Peter Gulutzan
Status:	Closed
Category:	Server	Severity:	S3 (Non-critical)
Version:	5.0.2-alpha-debug	OS:	Linux (SuSE 8.2)
Assigned to:		Target Version:

Description:
I have a table TPK with a primary key. I have a table TFK with a foreign key, referencing

TPK. I try to drop TPK. The drop fails. Good -- it should fail! But the error message is:

"Unknown table '...'". This is misleading. The table is known. The error message should
be: 
"There is a foreign-key '...' table that references '...'". 
 

How to repeat:
mysql> create table tpk (s1 int, primary key (s1)) engine=innodb; 
Query OK, 0 rows affected (0.40 sec) 
 
mysql> create table tfk (s1 int, foreign key (s1) references tpk (s1)) engine=innodb; 
Query OK, 0 rows affected (0.36 sec) 
 
mysql> drop table tpk; 
ERROR 1051 (42S02): Unknown table 'tpk'

Verified against latest BK source.

I agree with Peter.  I had to search the bug database to figure out what was wrong.  I had
a drop table if exists and it says "unknown" ...  frustrating. Thanks, --Chad

Hi!

This was fixed in 4.1.6.

The fix has probably propagated to 5.0, too.

Regards,

Heikki

InnoDB: Change error code to HA_ERR_ROW_IS_REFERENCED if we cannot DROP a parent table
referenced by a FOREIGN KEY constraint; this error number is less misleading than the
previous number HA_ERR_CANNOT_ADD_FOREIGN, but misleading still.

It looks this bug was fixed while ago, but noone closed
the bug report.

Dear doc team, please verify whether it was documented.

It was documented in the 4.1.6 change notes but there
was no bug number. I added it.