Should return a multi-dimentional array of the column details
Format:
Array [
[0] => Array [
'Field' => field name
'Type' => field type, (e.g. 'serial', 'smallnum' or 'identifier')
'NotNull' => nullable?, (true or false)
'Key' => indexed?, ('PRI' for primary key)
]
[1] => ...
[n] => ...