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HHH-4936 - Document JPA criteria queries 

git-svn-id: https://svn.jboss.org/repos/hibernate/core/trunk@18842 1b8cb986-b30d-0410-93ca-fae66ebed9b2
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Steve Ebersole 2010-02-19 21:16:50 +00:00
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entitymanager/src/main/docbook/en/master.xml
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@ -1,4 +1,4 @@
<?xml version='1.0' encoding="UTF-8"?> <?xml version='1.0' encoding='UTF-8'?>
<!-- <!--
~ Hibernate, Relational Persistence for Idiomatic Java ~ Hibernate, Relational Persistence for Idiomatic Java
~ ~
@ -21,72 +21,67 @@
~ Free Software Foundation, Inc. ~ Free Software Foundation, Inc.
~ 51 Franklin Street, Fifth Floor ~ 51 Franklin Street, Fifth Floor
~ Boston, MA 02110-1301 USA ~ Boston, MA 02110-1301 USA
--> --><!-- This document was created with Syntext Serna Free. -->
<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN" "http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd" [ <!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN" "http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd" [
<!ENTITY versionNumber "3.4.0.GA"> <!ENTITY versionNumber "3.4.0.GA">
<!ENTITY copyrightYear "2004"> <!ENTITY copyrightYear "2004">
<!ENTITY copyrightHolder "Red Hat Inc."> <!ENTITY copyrightHolder "Red Hat Inc.">
]> ]>
<book lang="en"> <book>
<bookinfo> <bookinfo>
<title>Hibernate EntityManager</title> <title>Hibernate EntityManager</title>
<subtitle>User guide</subtitle> <subtitle>User guide</subtitle>
<releaseinfo>&versionNumber;</releaseinfo> <releaseinfo>&versionNumber;</releaseinfo>
<mediaobject> <mediaobject>
<imageobject> <imageobject>
<imagedata fileref="images/hibernate_logo_a.png" format="png" /> <imagedata fileref="images/hibernate_logo_a.png" format="PNG"/>
</imageobject> </imageobject>
</mediaobject> </mediaobject>
</bookinfo> </bookinfo>
<toc/>
<preface>
<title>Introducing EJB3 Persistence</title>
<para>The EJB3 specification recognizes the interest and the success of
the transparent object/relational mapping paradigm. The EJB3 specification
standardizes the basic APIs and the metadata needed for any
object/relational persistence mechanism. <emphasis>Hibernate
EntityManager</emphasis> implements the programming interfaces and
lifecycle rules as defined by the EJB3 persistence specification. Together
with <emphasis>Hibernate Annotations</emphasis>, this wrapper implements a
complete (and standalone) EJB3 persistence solution on top of the mature
Hibernate core. You may use a combination of all three together,
annotations without EJB3 programming interfaces and lifecycle, or even
pure native Hibernate, depending on the business and technical needs of
your project. You can at all times fall back to Hibernate native APIs, or
if required, even to native JDBC and SQL.</para>
</preface>
<xi:include href="modules/architecture.xml" xmlns:xi="http://www.w3.org/2001/XInclude" />
<xi:include href="modules/configuration.xml" xmlns:xi="http://www.w3.org/2001/XInclude" />
<xi:include href="modules/entitymanagerapi.xml" xmlns:xi="http://www.w3.org/2001/XInclude" />
<xi:include href="modules/transactions.xml" xmlns:xi="http://www.w3.org/2001/XInclude" />
<xi:include href="modules/listeners.xml" xmlns:xi="http://www.w3.org/2001/XInclude" />
<xi:include href="modules/batch.xml" xmlns:xi="http://www.w3.org/2001/XInclude" />
<xi:include href="modules/query_ejbql.xml" xmlns:xi="http://www.w3.org/2001/XInclude" />
<xi:include href="modules/query_criteria.xml" xmlns:xi="http://www.w3.org/2001/XInclude" />
<xi:include href="modules/query_native.xml" xmlns:xi="http://www.w3.org/2001/XInclude" />
<bibliography> <bibliography>
<title>References</title> <title>References</title>
<biblioentry id="JPA2"> <biblioentry id="JPA2">
<abbrev id="JPA2_ABBREV">JPA 2 Specification</abbrev> <abbrev id="JPA2_ABBREV">JPA 2 Specification</abbrev>
<title>JSR 317: <trademark>Java</trademark> Persistence API, Version 2.0</title> <title>JSR 317: <trademark>Java</trademark> Persistence API, Version 2.0 </title>
<collab>Java Persistence 2.0 Expert Group</collab> <collab>
<collabname>Java Persistence 2.0 Expert Group</collabname>
</collab>
<copyright> <copyright>
<year>2009</year> <year>2009</year>
<holder>SUN MICROSYSTEMS, INC.</holder> <holder>SUN MICROSYSTEMS, INC.</holder>
</copyright> </copyright>
<bibliomisc> <bibliomisc>
<email>jsr-317-feedback@sun.com</email> <email>jsr-317-feedback@sun.com</email>
<ulink url="http://jcp.org/en/jsr/detail?id=317"/> <ulink url="http://jcp.org/en/jsr/detail?id=317">JSR 317 JCP Page</ulink>
</bibliomisc> </bibliomisc>
</biblioentry> </biblioentry>
</bibliography> </bibliography>
<toc/>
<preface>
<title>Introducing EJB3 Persistence</title>
<para>The EJB3 specification recognizes the interest and the success of
the transparent object/relational mapping paradigm. The EJB3 specification
standardizes the basic APIs and the metadata needed for any
object/relational persistence mechanism.
<emphasis>Hibernate EntityManager</emphasis>
implements the programming interfaces and
lifecycle rules as defined by the EJB3 persistence specification. Together
with<emphasis>Hibernate Annotations</emphasis>, this wrapper implements a
complete (and standalone) EJB3 persistence solution on top of the mature
Hibernate core. You may use a combination of all three together,
annotations without EJB3 programming interfaces and lifecycle, or even
pure native Hibernate, depending on the business and technical needs of
your project. You can at all times fall back to Hibernate native APIs, or
if required, even to native JDBC and SQL.
</para>
</preface>
<xi:include xmlns:xi="http://www.w3.org/2001/XInclude" href="modules/architecture.xml"/>
<xi:include xmlns:xi="http://www.w3.org/2001/XInclude" href="modules/configuration.xml"/>
<xi:include xmlns:xi="http://www.w3.org/2001/XInclude" href="modules/entitymanagerapi.xml"/>
<xi:include xmlns:xi="http://www.w3.org/2001/XInclude" href="modules/transactions.xml"/>
<xi:include xmlns:xi="http://www.w3.org/2001/XInclude" href="modules/listeners.xml"/>
<xi:include xmlns:xi="http://www.w3.org/2001/XInclude" href="modules/batch.xml"/>
<xi:include xmlns:xi="http://www.w3.org/2001/XInclude" href="modules/query_ejbql.xml"/>
<xi:include xmlns:xi="http://www.w3.org/2001/XInclude" href="modules/query_criteria.xml"/>
<xi:include xmlns:xi="http://www.w3.org/2001/XInclude" href="modules/query_native.xml"/>
</book> </book>

197
entitymanager/src/main/docbook/en/modules/query_criteria.xml
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@ -1,4 +1,4 @@
<?xml version='1.0' encoding="UTF-8"?> <?xml version='1.0' encoding='UTF-8'?>
<!-- <!--
~ Hibernate, Relational Persistence for Idiomatic Java ~ Hibernate, Relational Persistence for Idiomatic Java
~ ~
@ -22,17 +22,15 @@
~ 51 Franklin Street, Fifth Floor ~ 51 Franklin Street, Fifth Floor
~ Boston, MA 02110-1301 USA ~ Boston, MA 02110-1301 USA
--> -->
<!DOCTYPE chapter PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN" "http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd" []>
<!DOCTYPE chapter PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN" "http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd">
<chapter id="querycriteria"> <chapter id="querycriteria">
<title>JPA Criteria Queries</title> <title>Criteria Queries</title>
<note> <note>
<para> <para>
This chapter elaborates on the material discussed in This chapter elaborates on the material discussed in
<citetitle pubwork="chapter">Chapter 6 Criteria API</citetitle> of the <citetitle pubwork="chapter">Chapter 6 Criteria API</citetitle>
<biblioref linkend="JPA2" endterm="JPA2_ABBREV" />. of<citation>JPA 2 Specification</citation>.
</para> </para>
</note> </note>
@ -41,54 +39,66 @@
in terms of using interfaces and classes to represent various structural parts of a query in terms of using interfaces and classes to represent various structural parts of a query
such as the query itself, or the select clause, or an order-by, etc. They can also be such as the query itself, or the select clause, or an order-by, etc. They can also be
type-safe in terms of referencing attributes as we will see in a bit. Users of the older type-safe in terms of referencing attributes as we will see in a bit. Users of the older
Hibernate <interfacename>org.hibernate.Criteria</interfacename> query API will recognize Hibernate
<interfacename>org.hibernate.Criteria</interfacename>
query API will recognize
the general approach, though we believe the JPA API to be superior as it represents a clean the general approach, though we believe the JPA API to be superior as it represents a clean
look at the lessons learned from that API. There are essentially 2 phases to performing look at the lessons learned from that API. There are essentially 2 phases to performing
a criteria query: a criteria query:
</para>
<orderedlist> <orderedlist>
<listitem> <listitem>
<para><link linkend="querycriteria-building">Building the criteria instance</link></para> <para>
<para><link linkend="querycriteria-executing">Executing the criteria instance</link></para> <link linkend="querycriteria-building">Building the criteria instance</link>
</para>
</listitem>
<listitem>
<para>
<link linkend="querycriteria-executing">Executing the criteria instance</link>
</para>
</listitem> </listitem>
</orderedlist> </orderedlist>
</para>
<section id="querycriteria-building"> <section id="querycriteria-building">
<title>Criteria query building</title> <title>Criteria query building</title>
<para> <para>
Criteria queries are essentially an object graph, where each part of the graph Criteria queries are essentially an object graph, where each part of the graph
represents an increasing (as we navigate down this graph) more atomic part of represents an increasing (as we navigate down this graph) more atomic part of
query. The first step in performing a criteria query is building this graph. query. The first step in performing a criteria query is building this graph.
</para> </para>
<section id="querycriteria-builder"> <section id="querycriteria-builder">
<title>CriteriaBuilder</title> <title>CriteriaBuilder</title>
<para> <para>
The <interfacename>javax.persistence.criteria.CriteriaBuilder</interfacename> interface is the The
<interfacename>javax.persistence.criteria.CriteriaBuilder</interfacename>
interface is the
first thing with which you need to become acquainted to begin using criteria queries. Its role first thing with which you need to become acquainted to begin using criteria queries. Its role
is a factory for all the individual pieces of the criteria. You obtain a is a factory for all the individual pieces of the criteria. You obtain a
<interfacename>javax.persistence.criteria.CriteriaBuilder</interfacename> instance by calling <interfacename>javax.persistence.criteria.CriteriaBuilder</interfacename>
the <methodname>javax.persistence.EntityManagerFactory.getCriteriaBuilder</methodname> method: instance by calling
the
<methodname>javax.persistence.EntityManagerFactory.getCriteriaBuilder</methodname>
method:
</para> </para>
<programlisting>CriteriaBuilder builder = entityManagerFactory.getCriteriaBuilder();</programlisting> <programlisting>CriteriaBuilder builder = entityManagerFactory.getCriteriaBuilder();</programlisting>
</section> </section>
<section id="querycriteria-criteria"> <section id="querycriteria-criteria">
<title>CriteriaQuery creation</title> <title>CriteriaQuery creation</title>
<para> <para>
Once you have the <interfacename>javax.persistence.criteria.CriteriaBuilder</interfacename> reference Once you have the
<interfacename>javax.persistence.criteria.CriteriaBuilder</interfacename>
reference
you can begin building the pieces of the criteria query. First, you will need a you can begin building the pieces of the criteria query. First, you will need a
<interfacename>javax.persistence.criteria.CriteriaQuery</interfacename> instance. <interfacename>javax.persistence.criteria.CriteriaQuery</interfacename>
<interfacename>javax.persistence.criteria.CriteriaBuilder</interfacename> defines 3 methods instance.
for obtaining a <interfacename>javax.persistence.criteria.CriteriaQuery</interfacename> <interfacename>javax.persistence.criteria.CriteriaBuilder</interfacename>
defines 3 methods
for obtaining a
<interfacename>javax.persistence.criteria.CriteriaQuery</interfacename>
instance: instance:
</para> </para>
<itemizedlist> <itemizedlist>
<listitem> <listitem>
<programlisting><![CDATA[CriteriaQuery<T> createQuery(Class<T>)]]></programlisting> <programlisting><![CDATA[CriteriaQuery<T> createQuery(Class<T>)]]></programlisting>
@ -100,80 +110,153 @@
<programlisting><![CDATA[CriteriaQuery<Object> createQuery()]]></programlisting> <programlisting><![CDATA[CriteriaQuery<Object> createQuery()]]></programlisting>
</listitem> </listitem>
</itemizedlist> </itemizedlist>
<para> <para>
Each serves different purposes depending on the expected type of the query results. The type Each serves a different purpose depending on the expected type of the query results. The type
is "carried forward" to the <interfacename>javax.persistence.TypedQuery</interfacename> we is &quot;carried forward&quot; to the
create from this <interfacename>javax.persistence.criteria.CriteriaQuery</interfacename> as <interfacename>javax.persistence.TypedQuery</interfacename>
we will see <link linkend="querycriteria-executing">later</link>. we
create from this
<interfacename>javax.persistence.criteria.CriteriaQuery</interfacename>
as
we will see later in<xref linkend="querycriteria-executing"/>later.
</para> </para>
<section id="querycriteria-criteria-typed"> <section id="querycriteria-criteria-typed">
<title>Typed CriteriaQuery</title> <title>Typed CriteriaQuery</title>
<programlisting><![CDATA[CriteriaQuery<Person> personCriteria = builder.createQuery(Person.class);]]></programlisting> <programlisting>
<![CDATA[CriteriaQuery<Person> personCriteria = builder.createQuery(Person.class);]]></programlisting>
<para> <para>
Basically this is saying to create a criteria where the results of this query will be of type Basically this is saying to create a criteria where the results of this query will be of type
Person. Person might be an entity or it might not. The type could even be simple types like Person. Person might be an entity or it might not. The type could even be simple types like
<classname>java.lang.Integer</classname>, <classname>java.lang.String</classname>, etc. We <classname>java.lang.Integer</classname>,<classname>java.lang.String</classname>, etc. We
will discuss this topic in more detail in <xref linkend="querycriteria-selection"/> will discuss this topic in more detail in
<xref linkend="querycriteria-selection"/>
</para> </para>
</section> </section>
<section id="querycriteria-criteria-tuple"> <section id="querycriteria-criteria-tuple">
<title>Tuple CriteriaQuery</title> <title>Tuple CriteriaQuery</title>
<programlisting><![CDATA[CriteriaQuery<Tuple> personCriteria = builder.createTupleQuery();]]></programlisting> <programlisting>
<programlisting><![CDATA[CriteriaQuery<Tuple> personCriteria = builder.createQuery(Tuple.class);]]></programlisting> <![CDATA[CriteriaQuery<Tuple> personCriteria = builder.createTupleQuery();]]></programlisting>
<programlisting>
<![CDATA[CriteriaQuery<Tuple> personCriteria = builder.createQuery(Tuple.class);]]></programlisting>
<para> <para>
These two forms are exactly the same. Both say to create a criteria where the results of this These two forms are exactly the same. Both say to create a criteria where the results of this
query will be of type <interfacename>javax.persistence.Tuple</interfacename>. The term tuple is query will be of type<interfacename>javax.persistence.Tuple</interfacename>. The term tuple is
taken from mathematics, but its intent here is simply to mean a plurality; namely we are saying taken from mathematics, but its intent here is simply to mean a plurality; namely we are saying
that each query result will actually be multiple values, a projection. The that each query result will actually be multiple values, a projection. The
<interfacename>javax.persistence.Tuple</interfacename> instance gives us typed access to these <interfacename>javax.persistence.Tuple</interfacename>
instance gives us typed access to these
multiple result values after the query has been executed. We will discuss accessing the query multiple result values after the query has been executed. We will discuss accessing the query
results via a <interfacename>javax.persistence.Tuple</interfacename> in results via a
<interfacename>javax.persistence.Tuple</interfacename>
in
<xref linkend="querycriteria-executing"/>. <xref linkend="querycriteria-executing"/>.
</para> </para>
</section> </section>
<section id="querycriteria-criteria-untyped"> <section id="querycriteria-criteria-untyped">
<title>Untyped CriteriaQuery</title> <title>Untyped CriteriaQuery</title>
<programlisting><![CDATA[CriteriaQuery<Object> personCriteria = builder.createQuery();]]></programlisting> <programlisting>
<programlisting><![CDATA[CriteriaQuery<Object> personCriteria = builder.createQuery(Object.class);]]></programlisting> <![CDATA[CriteriaQuery<Object> personCriteria = builder.createQuery();]]></programlisting>
<programlisting>
<![CDATA[CriteriaQuery<Object> personCriteria = builder.createQuery(Object.class);]]></programlisting>
<para> <para>
These two forms are exactly the same. Both say to create a criteria where the results of this These two forms are exactly the same. Both say to create a criteria where the results of this
query could be anything. Not generally recommended as you obviously lose the type safety. query could be anything. Not generally recommended as you obviously lose the type safety.
</para> </para>
</section> </section>
</section> </section>
<section id="querycriteria-from"> <section id="querycriteria-from">
<title>FROM clause</title> <title>FROM clause</title>
<blockquote> <blockquote>
<attribution><biblioref linkend="JPA2" endterm="JPA2_ABBREV" /></attribution> <attribution>
<citation>
<citation>JPA 2 Specification</citation>
</citation>
</attribution>
<para> <para>
A CriteriaQuery object defines a query over one or more entity, embeddable, or basic abstract A CriteriaQuery object defines a query over one or more entity, embeddable, or basic abstract
schema types. The root objects of the query are entities, from which the other types are reached schema types. The root objects of the query are entities, from which the other types are reached
by navigation. by navigation.
</para> </para>
</blockquote> </blockquote>
<para>All the individual parts of the FROM clause (roots, joins, paths) implement the
<interfacename>javax.persistence.criteria.From</interfacename>
interface.
</para>
<section id="querycriteria-from-root"> <section id="querycriteria-from-root">
<title>Roots</title> <title>Roots</title>
<para> <para>Roots define the basis from which all joins, paths and attributes are available in the query. It
is
the root of the portion of your domain model you wish to query against. In a criteria query, a root
is always an entity. Roots are defined and added to the criteria by the overloaded
<methodname>from</methodname>
methods on<interfacename>javax.persistence.criteria.CriteriaQuery</interfacename>:
</para> </para>
<programlisting><![CDATA[<X> Root<X> from(Class<X>)]]></programlisting>
<programlisting><![CDATA[<X> Root<X> from(EntityType<X>)]]></programlisting>
<programlisting><![CDATA[CriteriaQuery<Person> personCriteria = builder.createQuery( Person.class );
// create and add the root
person.from( Person.class );
...]]></programlisting>
<para>Criteria queries may define multiple roots, the effect of which is to create a cartesean product
between the newly added root and the others. Here is an example matching all single men and all
single women:
</para>
<programlisting><![CDATA[CriteriaQuery query = builder.createQuery();
Root<Person> men = query.from( Person.class );
Root<Person> women = query.from( Person.class );
Predicate menRestriction = builder.and(
builder.equal(
men.get( Person_.gender ),
Gender.MALE
),
builder.equal(
men.get( Person_.relationshipStatus ),
RelationshipStatus.SINGLE
)
);
Predicate womenRestriction = builder.and(
builder.equal(
women.get( Person_.gender ),
Gender.FEMALE
),
builder.equal(
women.get( Person_.relationshipStatus ),
RelationshipStatus.SINGLE
)
);
query.where(
builder.and( menRestriction, womenRestriction )
);]]></programlisting>
</section> </section>
<section id="querycriteria-from-join"> <section id="querycriteria-from-join">
<title>Joins</title> <title>Joins</title>
<para>todo</para> <para>Joins allow navigation from other
<interfacename>javax.persistence.criteria.From</interfacename>
to either association or embedded attributes. Joins are created by the numerous overloaded
<methodname>join</methodname>
methods of the
<interfacename>javax.persistence.criteria.From</interfacename>
interface:
</para>
<programlisting><![CDATA[CriteriaQuery<Person> personCriteria = builder.createQuery( Person.class );
Root<Person> personRoot = person.from( Person.class );
// Person.address is an embedded attribute
Join<Person,Address> personAddress = personRoot.join( Person_.address );
// Address.country is a ManyToOne
Join<Address,Country> addressCountry = personAddress.join( Address_.country );
...]]></programlisting>
<para>An example with collection attributes:</para>
<programlisting><![CDATA[CriteriaQuery<Person> personCriteria = builder.createQuery( Person.class );
Root<Person> personRoot = person.from( Person.class );
Join<Person,Order> orders = personRoot.join( Person_.orders );
Join<Order,LineItem> orderLines = orders.join( Order_.lineItems );
...]]></programlisting>
</section> </section>
<section id="querycriteria-from-fetch"> <section id="querycriteria-from-fetch">
<title>Fetches</title> <title>Fetches</title>
<para>todo</para> <para>todo</para>
</section> </section>
</section> </section>
<section id="querycriteria-path"> <section id="querycriteria-path">
<title>Path expressions</title> <title>Path expressions</title>
<note> <note>
@ -183,22 +266,17 @@
</note> </note>
<para>todo</para> <para>todo</para>
</section> </section>
<section id="querycriteria-selection"> <section id="querycriteria-selection">
<title>Selections</title> <title>Selections</title>
<para>todo</para> <para>todo</para>
</section> </section>
</section> </section>
<section id="querycriteria-executing"> <section id="querycriteria-executing">
<title>Criteria query execution</title> <title>Criteria query execution</title>
<para>todo</para> <para>todo</para>
</section> </section>
<section id="querycriteria-common"> <section id="querycriteria-common">
<title>Common use cases</title> <title>Common use cases</title>
<section id="querycriteria-common-selectroot"> <section id="querycriteria-common-selectroot">
<title>Selecting the root entity</title> <title>Selecting the root entity</title>
<programlisting><![CDATA[// get all people with brown eyes <programlisting><![CDATA[// get all people with brown eyes
@ -211,7 +289,6 @@ personCriteria.select( personRoot );
personCriteria.where( builder.equal( Person_.eyeColor, "brown" ) ); personCriteria.where( builder.equal( Person_.eyeColor, "brown" ) );
List<Person> people = em.createQuery( personCriteria ).getResultList();]]></programlisting> List<Person> people = em.createQuery( personCriteria ).getResultList();]]></programlisting>
</section> </section>
<section id="querycriteria-common-selectassociation"> <section id="querycriteria-common-selectassociation">
<title>Selecting an association</title> <title>Selecting an association</title>
<programlisting><![CDATA[// get the gender of all people with brown eyes <programlisting><![CDATA[// get the gender of all people with brown eyes
@ -224,7 +301,6 @@ personCriteria.select( personRoot );
personCriteria.where( builder.equal( Person_.eyeColor, "brown" ) ); personCriteria.where( builder.equal( Person_.eyeColor, "brown" ) );
List<Person> people = em.createQuery( personCriteria ).getResultList();]]></programlisting> List<Person> people = em.createQuery( personCriteria ).getResultList();]]></programlisting>
</section> </section>
<section id="querycriteria-common-selectvalue"> <section id="querycriteria-common-selectvalue">
<title>Selecting a value</title> <title>Selecting a value</title>
<programlisting><![CDATA[// get the height of all people with brown eyes <programlisting><![CDATA[// get the height of all people with brown eyes
@ -234,7 +310,6 @@ personCriteria.select( personRoot.get( Person.height ) );
personCriteria.where( builder.equal( Person_.eyeColor, "brown" ) ); personCriteria.where( builder.equal( Person_.eyeColor, "brown" ) );
List<Integer> heights = em.createQuery( personCriteria ).getResultList();]]></programlisting> List<Integer> heights = em.createQuery( personCriteria ).getResultList();]]></programlisting>
</section> </section>
<section id="querycriteria-common-selectaggregation"> <section id="querycriteria-common-selectaggregation">
<title>Selecting an aggregated value</title> <title>Selecting an aggregated value</title>
<programlisting><![CDATA[// get the maximum height of all people with brown eyes <programlisting><![CDATA[// get the maximum height of all people with brown eyes
@ -244,7 +319,6 @@ personCriteria.select( builder.max( personRoot.get( Person.height ) ) );
personCriteria.where( builder.equal( Person_.eyeColor, "brown" ) ); personCriteria.where( builder.equal( Person_.eyeColor, "brown" ) );
Integer maxHeight = em.createQuery( personCriteria ).getSingleResult();]]></programlisting> Integer maxHeight = em.createQuery( personCriteria ).getSingleResult();]]></programlisting>
</section> </section>
<section id="querycriteria-common-selecttuple"> <section id="querycriteria-common-selecttuple">
<title>Selecting a tuple</title> <title>Selecting a tuple</title>
<programlisting><![CDATA[// get the id, height and gender of all people with brown eyes <programlisting><![CDATA[// get the id, height and gender of all people with brown eyes
@ -266,7 +340,6 @@ for ( Tuple tuple : tuples ) {
handleId( tuple.get( "id" ) ); handleId( tuple.get( "id" ) );
}]]></programlisting> }]]></programlisting>
</section> </section>
<section id="querycriteria-common-selectconstruct"> <section id="querycriteria-common-selectconstruct">
<title>Selecting a constructed value</title> <title>Selecting a constructed value</title>
<programlisting><![CDATA[// get the id, height and gender of all people with brown eyes <programlisting><![CDATA[// get the id, height and gender of all people with brown eyes
@ -283,7 +356,6 @@ personCriteria.select(
); );
List<PersonHolder> people = em.createQuery( personCriteria ).getResultList();]]></programlisting> List<PersonHolder> people = em.createQuery( personCriteria ).getResultList();]]></programlisting>
</section> </section>
<section id="querycriteria-common-param"> <section id="querycriteria-common-param">
<title>Using parameters</title> <title>Using parameters</title>
<programlisting><![CDATA[// get all people with brown eyes <programlisting><![CDATA[// get all people with brown eyes
@ -297,5 +369,4 @@ query.setParameter( eyeColorParam, "brown" );
List<Person> people = query.getResultList();]]></programlisting> List<Person> people = query.getResultList();]]></programlisting>
</section> </section>
</section> </section>
</chapter> </chapter>