Question

I’m still quite a mySQL newbie, so I would like to do this right to avoid future mishaps.

What is the right way to detect when do I need to UPDATE an entry in a table or INSERT a new one?

Thank you.

Answer 1

If you want to insert a record if a value does not exist in a certain column, or update it when it exists, you should declare a UNIQUE constraint on the column and use this syntax:

INSERT
INTO    mytable (key, value)
VALUES  ($newkey, $newvalue)
ON DUPLICATE KEY UPDATE
SET     value = $newvalue