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Re: AW: [eclipselink-users] questiona about JPQL and Collections
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Try calling readAllQuery.dontUseDistinct().
-Tom
Daniel.Stucky@xxxxxxxxxxx wrote:
Hi Tom,
thanks for your help, in general it works as described by you.
However, I forgot to include the following member of RecordDao in the sample code:
@Column(name = "RECORD")
private byte[] _serializedRecord;
The generated SQL query contains DISTINCT, which is not usable with queries containing BLOBs.
Any suggestions how to handle this ?
Bye,
Daniel
-----Ursprüngliche Nachricht-----
Von: eclipselink-users-bounces@xxxxxxxxxxx [mailto:eclipselink-users-
bounces@xxxxxxxxxxx] Im Auftrag von Tom Ware
Gesendet: Mittwoch, 28. Januar 2009 21:12
An: EclipseLink User Discussions
Betreff: Re: [eclipselink-users] questiona about JPQL and Collections
Hi Daniel,
Because BasicCollection is not a part of the JPA specification yet,
JPQL
cannot currently query across BasicCollections. (That behavior is
expected in
the upcoming JPA 2.0 specification)
To access a BasicCollection in a query, you will have to use
EclipseLink's
criteria API instead.
Your code will look something like this:
ReadAllQuery query = new ReadAllQuery(RecordDAO.class);
ExpressionBuilder record = new ExpressionBuilder();
Expression attributes = record.anyOfAttributes("attributes");
Expresion criteria =
attributes.get("_name").equal(record.getParameter("name"));
criteria =
criteria.and(attributes.anyOf("_values").equal(record.getParameter("val
ue")))
query.setSelectionCriteria(criteria);
This query can be added as a named query through a SessionCustomizer by
calling
the addQuery(name, query) method.
That is the basics of how it should look. With a little massaging
of the
code, it should be possible to use this query just like any other named
query in
JPA.
BTW: Here is the Customizer doc:
http://wiki.eclipse.org/Using_EclipseLink_JPA_Extensions_%28ELUG%29#Usi
ng_EclipseLink_JPA_Extensions_for_Customization_and_Optimization
-Tom
Daniel.Stucky@xxxxxxxxxxx wrote:
Hi all,
given the following Entities, how can I express a named query that
selects all Records where AttributeDao._name = "X" and
AttributeDao._values.contains("Y")
@Entity
@Table(name = "RECORDS")
public class RecordDao implements Serializable {
@Id
@Column(name = "ID")
private String _idString;
@Column(name = "SOURCE")
private String _source;
...
}
@Entity
@Table(name = "ATTRIBUTES")
public class AttributeDao {
@Id
@GeneratedValue(strategy=GenerationType.AUTO)
@Column(name = "ATT_ID")
private String _id;
@Column(name = "ATT_NAME")
private String _name;
@BasicCollection (
fetch=FetchType.EAGER,
valueColumn=@Column(name="ATT_VALUE"))
@CollectionTable (
name="ATTRIBUTE_VALUES",
primaryKeyJoinColumns=
{@PrimaryKeyJoinColumn(name="ATT_ID",
referencedColumnName="ATT_ID")}
)
private List<String> _values;
...
}
I tried something like this
@NamedQueries({
@NamedQuery(name="RecordDao.findByAttribute",
query="SELECT DISTINCT r FROM RecordDao r JOIN r._attributes a
JOIN a._values v WHERE a._name = :name AND v._values = :value")
})
but during EntityManager creation I get the following error:
Exception [EclipseLink-8030] (Eclipse Persistence Services - 1.0.2
(Build 20081024)): org.eclipse.persistence.exceptions.JPQLException
Exception Description: Error compiling the query
[RecordDao.findByAttribute: SELECT DISTINCT r FROM RecordDao r JOIN
r._attributes a JOIN a._values v WHERE a._name = :name AND v._values
=
:value], line 1, column 63: unknown state or association field
[_values]
of class [org.eclipse.smila.datamodel.persistence.AttributeDao].
I expect the syntax for "AND v._values = :value" to be not valid, but
I
wonder why it complains about JOIN a._values v.
Anyone any ideas/suggestions ?
Bye,
Daniel
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