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Using Date type in an EJB Query Language

Posted on 2008-10-07
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Last Modified: 2013-12-14
I am developing an application in NetBeans thats uses the built in database server (apache derby), i've used the IDE to generate entity classes refelecting tables in my database. The IDE has also created a persistance unit and an entity manager, i am trying to run an EJB Query on a table in the database but i am having some syntactical difficulties which i am having trouble resolving.

This is the EJB QL:

SELECT m FROM Measurement m WHERE m.measurementDateofbooking = '07.10.2008'

This is the Measurement Table Structure in the database:

MEASUREMENT                             Data Type
=====================================
measurement_id                           Auto Gen Int PK
measurement_customer_id          Int FK
measurement_dateofbooking       Date
measurement_timeofbooking       Time
measurement_completed             Char

This is a relevant snippet of the measurement Entity Class: (See Code Snippet)

This is the exception i recieve:

Exception Description: The object [07.10.2008], of class [class java.lang.String], from mapping [oracle.toplink.essentials.mappings.DirectToFieldMapping[measurementDateofbooking-->MEASUREMENT."measurement_dateofbooking"]] with descriptor [RelationalDescriptor(mk_carpets_alpha_entity_classes.Measurement --> [DatabaseTable(MEASUREMENT)])], could not be converted to [class java.sql.Date].

Exception in thread "AWT-EventQueue-0" Local Exception Stack:

Exception [TOPLINK-3002] (Oracle TopLink Essentials - 2.0.1 (Build b09d-fcs (12/06/2007))): oracle.toplink.essentials.exceptions.ConversionException

Exception Description: The object [07.10.2008], of class [class java.lang.String], from mapping [oracle.toplink.essentials.mappings.DirectToFieldMapping[measurementDateofbooking-->MEASUREMENT."measurement_dateofbooking"]] with descriptor [RelationalDescriptor(mk_carpets_alpha_entity_classes.Measurement --> [DatabaseTable(MEASUREMENT)])], could not be converted to [class java.sql.Date].

        at oracle.toplink.essentials.exceptions.ConversionException.incorrectDateFormat(ConversionException.java:119)
        at oracle.toplink.essentials.internal.helper.Helper.dateFromString(Helper.java:747)


After looking at the exception i thought it might be the format of the date, but i tried the same date in the database sql command ('07.10.2008') and it retrieved the results fine. I even tried changing my EJB Q to this: SELECT m FROM Measurement m WHERE m.measurementDateofbooking = new Date(2008,10,7)
and it still didnt work.
package mk_carpets_alpha_entity_classes;
 
import java.beans.PropertyChangeListener;
import java.beans.PropertyChangeSupport;
import java.io.Serializable;
import java.util.Date;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.ManyToOne;
import javax.persistence.NamedQueries;
import javax.persistence.NamedQuery;
import javax.persistence.Table;
import javax.persistence.Temporal;
import javax.persistence.TemporalType;
import javax.persistence.Transient;
 
/**
 *
 * @author ______
 */
@Entity
@Table(name = "MEASUREMENT")
@NamedQueries({@NamedQuery(name = "Measurement.findByMeasurementId", query = "SELECT m FROM Measurement m WHERE m.measurementId = :measurementId"), @NamedQuery(name = "Measurement.findByMeasurementDateofbooking", query = "SELECT m FROM Measurement m WHERE m.measurementDateofbooking = :measurementDateofbooking"), @NamedQuery(name = "Measurement.findByMeasurementTimeofbooking", query = "SELECT m FROM Measurement m WHERE m.measurementTimeofbooking = :measurementTimeofbooking"), @NamedQuery(name = "Measurement.findByMeasurementCompleted", query = "SELECT m FROM Measurement m WHERE m.measurementCompleted = :measurementCompleted")})
public class Measurement implements Serializable {
    @Transient
    private PropertyChangeSupport changeSupport = new PropertyChangeSupport(this);
    private static final long serialVersionUID = 1L;
    @Id
    @Column(name = "\"measurement_id\"", nullable = false)
    private Integer measurementId;
    @Column(name = "\"measurement_dateofbooking\"", nullable = false)
    @Temporal(TemporalType.DATE)
    private Date measurementDateofbooking;
    @Column(name = "\"measurement_timeofbooking\"", nullable = false)
    @Temporal(TemporalType.TIME)
    private Date measurementTimeofbooking;
    @Column(name = "\"measurement_completed\"")
    private Character measurementCompleted;
    @JoinColumn(name = "\"measurement_customer_id\"", referencedColumnName = "\"customer_id\"")
    @ManyToOne
    private Customer measurementCustomerId;

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Question by:awax187
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Accepted Solution

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awax187 earned 0 total points
ID: 22663974
ok never mind ive solved the problem. The date in the EJB Query should have been in the format, 'yyyy-mm-dd' i was writing it in the wrong form. Hope somebody finds this useful.
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