customConstraintOperator
Sets the custom constraint operator code to return to SQLite.
By default, if VirtualTable.findFunction returns a non-null function, one is returned to SQLite to indicates that the function is overloaded, and zero is returned otherwise.
If a custom code is set, it is returned, with the scalar function, instead of the default one. However, if no scalar function is returned but a custom code is set, then an exception is thrown.
Note that this replaces any code from a previous call to customConstraintOperator.