I'm planning on adding storage for configuration options to the website I'm working on (php + MySQL).
The problem is that I cannot decide between having a 2-column table (with key and value fields) that contains multiple rows, one for each option; or an n-column table with one row.
It seems like using the single row format is superior, because each field can have the proper data type (INT, VARCHAR, etc.) and would make fetching all configuration values easier (single-row), but adding a new option would mean a new field every time.
At the same time, though, it seems like having a key-value table would possibly be a performance issue since you'd have to fetch all rows to get the full configuration, as well as updating having to find and seek the proper row to update; you also don't get actual typing (and would have to rely on VARCHAR or TEXT only).
I'm not planning on having a lot of configuration options (maybe 20 at the most, more likely 5-10), so I'm not sure if key-value or multi-field is the way to go, here.
Best Answer
I did this with a project recently, only I had even fewer settings to store. I opted for using a two column table, with each setting being it's own row.
I think there are pluses and minuses to each, but if you're dealing with such a small set of configuration options, there is not going to be a huge performance hit. To put into perspective, phpBB's config table has almost 270 rows of config options.