split query and prepared statement
DRY
implement join
add sql insert change sql query one behaviour to only return object
add sql delete
add update
remove this beast
clean DBConnection
use specific exception
use the right type of exception
fix database not connected things
remove non existant file
add xml settings and generate program
clean up DataModel a little bit
add assert for delete command return value
update query spec
use === instead of ==, don't test value == null twice
use right type of exception
no need for this
use right type of exception: InvalidArgumentException