This is a great way to reduce MySQL code/mistakes/annoyance when doing things, take for example this statement:
INSERT IGNORE INTO sometable(CatName) VALUES("someitem"
);
Notice the "IGNORE", that is what does the magic.
Normally if the entry "someitem" existed you'd get an error message back such as "Duplicate entry for whatever". What I have normally done in PHP or whatever language is manually coded or made a helper function to return true/false if the same result/name already exists in the database.
Just note that the syntax has changed from a normal INSERT.
mysql, insert, duplicate, entry, existthis, reduce, annoyance, sometable, catname, quot, someitem, php, manually, coded, helper, database, syntax,