A Developer's Scrappad

EJB3 JPA: 3 Ways Of Generating Primary Key Through @GeneratedValue

Let’s face it, different Databases have different ways of generating primary key values, either in the form of identity or through a sequence generator, if the primary key field is of a numerical data type. While coding Entity classes, it is necessary to define whether the primary key value (if is it of numerical type) could be generated from the sequence generator, self generated and inserted in the database during persistent or just self define. There are also times whereby your application would rather depend on a custom created table in the DB just to store generated sequential numbers as primary keys for the Entity. So, in this article, we’ll explore 3 ways in dealing with generating primary key values with the databases that support it and how to use the @GeneratedValue annotation effectively.
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