Seeking basic run down of php and database

[MikiHeart]

Hey, a little update on the script I was working on. If the user updates their profile, and select no pet, it becomes set to 0, this this happens:

Fatal error: Uncaught exception 'AdoptNotfoundException' with message 'Adoptable ID 0 does not exist or does not belong to the owner specified...' in C:\wamp\www\micronoms\classes\class_ownedadoptable.php on line 26
( ! ) AdoptNotfoundException: Adoptable ID 0 does not exist or does not belong to the owner specified... in C:\wamp\www\micronoms\classes\class_ownedadoptable.php on line 26

I'll do some more work on it.

Edit:

I fixed it XD With one minor change!

From:

if ($this->userfavpet == "0"){

To:

if ($this->userfavpet == "0" or $this->userfavpet == ""){