Jakarta Persistence Query Language: Difference between revisions

Revision as of 08:24, 18 September 2018

Revision as of 21:15, 21 May 2020

Line 31:

Example JPA Classes, getters and setters omitted for simplicity.

<sourcesyntaxhighlight lang="java">

@Entity

public class Author {

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private List<Book> books;

}

</syntaxhighlight>

</source>

Then a simple query to retrieve the list of all authors, ordered alphabetically, would be:

<sourcesyntaxhighlight lang="sql">

SELECT a FROM Author a ORDER BY a.firstName, a.lastName

</syntaxhighlight>

</source>

To retrieve the list of authors that have ever been published by XYZ Press:

<sourcesyntaxhighlight lang="sql">

SELECT DISTINCT a FROM Author a INNER JOIN a.books b WHERE b.publisher.name = 'XYZ Press'

</syntaxhighlight>

</source>

JPQL supports named parameters, which begin with the colon (<code>:</code>). We could write a function returning a list of authors with the given last name as follows:

<sourcesyntaxhighlight lang="java">

import javax.persistence.EntityManager;

import javax.persistence.TypedQuery;

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return query.getResultList();

}

</syntaxhighlight>

</source>

==Hibernate Query Language==