Originally Posted by etoolbox

What field type and size is your primary key?

Originally Posted by codeguy

Since you seem to expect image_id to increment from submitting a null value, I assume auto_increment was specified for image_id.

my guess is the same as where i think etoolbox was going. Use a larger int (guessing image_id is tinyint) small int/medium int/int (i'd prolly recommend Int).

Originally Posted by tony

Without knowing the type like etoolbox said it's kind of hard.
If it is a primary key, it is not safe to leave it a null, so the record is not created. That could be the reason.
If the image_id is set to auto_increment, you don't need to make an explicit insert with that field, something like this would work:

But I might be wrong, I just finished a project working with Access SQL so that might not be right. If that is not right try to save the default value like this:

I am no expert in mysql though, this is just speculations, but maybe it would help.

Originally Posted by etoolbox

My guess is it's a tinyint with a max integer value of 127. You cannot insert a value > 127 into this field. What MySQL "helpfully" does is to try to make it the highest value if it's not specified and because that key already exists you get a "duplicate entry" error when in fact that's not the real error, it's that you have an overflow on the PK.

Originally Posted by Salathe

I'd also go with the unsigned tinyiny column theory. The tinyint (when unsigned) has a max value of 127. Trying to insert a new auto_incremented value higher than that will indeed raise the "Duplicate entry '127' for key 1".