The Template Method Pattern

The Template Method is a pattern intended to help one abstract out a common process from different procedures. According to the Gang of Four, the intent of the Template method is to

Define the skeleton of an algorithm in an operation, deferring some steps to subclasses. Redefine the steps in an algorithm without changing the algorithm's structure.^[1]

^[1] Gamma, E., Helm, R., Johnson, R., Vlissides, J., Design Patterns: Elements of Reusable Object-Oriented Software, Reading, Mass.: Addison-Wesley, 1995, p. 325.

In other words, although there are different methods for connecting and querying Oracle databases and SQL Server databases, they share the same conceptual process. The Template Method gives us a way to capture this common ground in an abstract class while encapsulating the differences in derived classes. The Template Method pattern is about controlling a sequence common to different processes.