We also activated a database action to drop and create the database schema automatically. We added properties to specify the JDBC connection URL and the database user and password. This is an advanced topic we won’t cover in this article. In this example we want JPA to manage the transactions, but in more complex scenarios that require distributed transactions across multiple databases or services like JMS and JCA, we would use JTA instead. The transaction type indicates who manages the transactions, JPA or the server. Every Persistence Unit needs a name that we can use later in the code. Pay close attention to the name and transaction-type parameters. If you are looking for a comprehensive course on JPA or Hibernate, I recommend reading the JPA spec and the official Hibernate docs. We’ll use only standard features and cover only the basics. This article gets you started with the Hibernate implementation of JPA. Another advantage is that someone with experience in, say EclipseLink or Apache OpenJPA, then they can use at least part of that experience when moving to Hibernate. One potential advantage of using it with JPA is that you can move between implementations if you want (something I have never seen happening, though). You can use Hibernate ORM without JPA or through JPA. The most popular JPA implementation is Hibernate ORM. JPA is an API specification that someone can implement–JPA providers or implementations. JPA solves the object-relational impedance mismatch by allowing you to map Java objects to database tables and is one of the most (if not the most) used persistence frameworks for Java. When Java EE was donated to the Eclipse Foundation under the Jakarta EE project, the name of the API changed to Jakarta Persistence but the term JPA is still in use. JPA was born as the acronym for Java Persistence API.
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