Sometimes it is convenient to write applications that can work with many different SQL based databases.
Some database abstraction packages can help writing applications that can work unchanged with different databases.
However, if you start using SQL code that uses features that are specific of certain databases, it will be harder to make the applications work with other databases later.
This class can help avoiding some SQL portability problems by converting the SQL code that you use into SQL code that does not use certain database specific features known by the class.