I may have either misunderstood how to use the ON DUPLICATE KEY syntax, alternatively my database structure needs some work but here goes.
I have a table (bookings-meta) which represents meta data associated with another table (bookings) , different rows in the bookings table may or may not have specific meta data associated with them in the other table.
The bookings-meta table has the following columns, meta_id (primary key), booking_id, key and value.
From my understanding, to use ON DUPLICATE KEY I need to know what in this case is the meta_id, often this isn't the case, I'm trying to simply push a key, value pair to the table using the booking_id, so if the particular key exists then its replaced otherwise its inserted.
At the moment I have a seperate query to try to select the row, if its found then I UPDATE, if not then its an INSERT.
Is there a way of doing an insert/update in one query without using ON DUPLICATE KEY or have I missed a trick with this one?