Drop constraints only if it exists in mysql server 5.0

Question

i want to know how to drop a constraint only if it exists. is there any single line statement present in mysql server which will allow me to do this.

i have tried the following command but unable to get the desire output

alter table airlines 
drop foreign key if exits FK_airlines;

any help to this really help me to go forward in mysql

Answer 1

I do not believe this is possible in a single line, unless you are willing to detect the error and move on (not a bad thing).

The INFORMATION_SCHEMA database contains the info you need to tell if the foreign key exists, so you could implement it in a 2 step process.

http://dev.mysql.com/doc/refman/5.1/en/table-constraints-table.html