What's the problem?
===================
TL;DR: When the user enters an incorrect default value, its
corresponding param-input will disappear
When creating a parameter from SQL, we perform cast_to_ruby, which means
that if the default value given by the user is invalid, the entire
parameter will not be added to the param_list of the query.
This behavior is very confusing, and users will not understand why an
incorrect initial value will cause the param-input to disappear.
What's the fix?
================
The cast_to_ruby process is canceled in create_from_sql, so that
param-input with incorrect default value will still be displayed.
We have a simple validation process on the front end, which is enough to
prompt whether some default inputs are incorrect.