1.1. What is persistence?

Almost all applications require persistent data. Persistence is one of the fundamental concepts in application development. If an information system didn't preserve data when it was powered off, the system would be of little practical use. When we talk about persistence in Java, we're normally talking about storing data in a relational database using SQL. We'll start by taking a brief look at the technology and how we use it with Java. Armed with that information, we'll then continue our discussion of persistence and how it's implemented in object-oriented applications.

1.1.1. Relational databases

You, like most other developers, have probably worked with a relational database. Most of us use a relational database ...

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