Functional wrappers for JDBC

We now have a basic overview of the tools afforded by JDBC. All the objects that we have interacted with so far feel somewhat clunky and out of place in Scala. They do not encourage a functional style of programming.

Of course, elegance is not necessarily a goal in itself (or, at least, you will probably struggle to convince your CEO that he should delay the launch of a product because the code lacks elegance). However, it is usually a symptom: either the code is not extensible or too tightly coupled, or it is easy to introduce bugs. The latter is particularly the case for JDBC. Forgot to check wasNull? That will come back to bite you. Forgot to close your connections? You'll get an "out of memory exception" (hopefully not in production).

In the next sections, we will look at patterns that we can use to wrap JDBC types in order to mitigate many of these risks. The patterns that we introduce here are used very commonly in Scala libraries and applications. Thus, besides writing robust classes to interact with JDBC, learning about these patterns will, I hope, give you greater understanding of Scala programming.