Talk:Jakarta Persistence Query Language: Difference between revisions

Revision as of 19:23, 26 April 2010

Revision as of 15:20, 29 September 2012

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{{WikiProject Java|class=stub|importance=low}}

== Mistake in example? ==

This article currently has the following example:

<source lang="java">

import javax.persistence.EntityManager;

import javax.persistence.Query;

import org.apache.commons.lang.StringUtils;

...

@SuppressWarnings("unchecked")

public List<Author> getAuthorsByLastName(String lastName) {

String queryString = "SELECT a FROM Author a " +

"WHERE :lastName IS NULL OR LOWER(a.lastName) = :lastName";

Query query = getEntityManager().createQuery(queryString);

query.setParameter("lastName", StringUtils.lowerCase(lastName));

return query.getResultList();

}

</source>

(Keep in mind the Author class has a field <code>private String firstName</code>.)

The <code>WHERE :lastName IS NULL</code> part doesn't make sense to me. Shouldn't it be written <code>WHERE lastName IS NULL</code> (i.e., without the colon)? In case I'm wrong, can someone please explain the semantics of this query? --[[User:Abdull|Abdull]] ([[User talk:Abdull|talk]]) 15:20, 29 September 2012 (UTC)