Exception [EclipseLink-4002] while using native query for joining two tables

StackOverflow https://stackoverflow.com/questions/15824562

Question

I have 2 tables Sponsors and Study. The columns in Sponsor and Study tables are:

Sponsors table structure:

SponsorId: int primary key auto_increment,
SponsorName: varchar(30) unique not null,
Address: varchar(255)

Study table structure:

StudyId int primary key auto_increment,
StudyName varchar(30) unique not null,
SponsorId int not null foreign key to Sponsors table.

Study to Sponsor has a ManyToOne relationship.

I am trying to display the fields in Sponsors and Study in a datatable and perform create, update and delete operations on it.

This is the method I have used for populating the datatable.

public List retrieveStudy() {
  Query query=getEntityManager().createNativeQuery("select"+    
              "s.studyId,s.studyName,s.sponsorId ,sp.sponsorName as"+    
              "sponsorName,sp.address from Study s left join Sponsors sp", 
               Study.class);
    return query.getResultList();
}

While displaying the datatable for Study I want to display the SponsorName instead of SponsorId so, I have used the join query for getting the SponsorName.

Now I am able to display the SponsorName in the datatable but when I add a record I am getting the following exception.

[EclipseLink-4002] (Eclipse Persistence Services - 2.2.0.v20110202-r8913):    orgException .eclipse.persistence.exceptions.DatabaseException
Internal Exception: com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: Unknown column 'SponsorName' in 'field list'
Error Code: 1054

This is my entity class for Study

public class Study implements Serializable {
private static final long serialVersionUID = 1L;
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
@Basic(optional = false)
@Column(name = "StudyId")
private Integer studyId;
@Basic(optional = false)
@NotNull
@Size(min = 1, max = 50)
@Column(name = "StudyName")
private String studyName;
@JoinColumn(name = "SponsorId", referencedColumnName = "SponsorId")
@ManyToOne(optional = false)
private Sponsors sponsorId;

@Column(name="SponsorName")
private String sponsorName;

// Constructors getters,setters
}

Jsf page

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"   
   "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml"
  xmlns:h="http://java.sun.com/jsf/html"
  xmlns:f="http://java.sun.com/jsf/core"
  xmlns:ui="http://java.sun.com/jsf/facelets"
  xmlns:p="http://primefaces.org/ui">

    <ui:composition template="/SRAtemplate.xhtml">
        <ui:define name="head">
            <title> Study </title>            
        </ui:define>
    <ui:define name="heading">
        Study 
    </ui:define>
    <ui:define name="body">
        <br/>
        <p:growl id="msg" autoUpdate="true"/>
        <br/>
        <h:form id="addstudyform">
            <p:panelGrid columns="2" styleClass="panelgridstyle">

                <f:facet name="header">
                    Add Study
                </f:facet>

                <h:outputLabel for="StudyName" value="StudyName*:"/>
                <p:inputText id="StudyName" value="#studyController.selected.studyName}" maxlength="20" 
                     required="true" requiredMessage="StudyName must be   entered"
                         validatorMessage="StudyName must be an alphanumeric value">
                    <f:validateRegex pattern="[a-zA-Z0-9\s]+"/>
                </p:inputText>

                <h:outputLabel for="Sponsor" value="Sponsor*:"/>
                <p:selectOneMenu id="Sponsor" value="#{studyController.selected.sponsorId}" effect="fade" effectSpeed="0" 
                       required="true" requiredMessage="Sponsor must be selected">  
                    <f:selectItems value="#{sponsorsController.itemsAvailableSelectOne}" var="sponsor" 
                           itemLabel="#{sponsor.sponsorId}" itemValue="#{sponsor}"/>  
                </p:selectOneMenu>

                <p:commandButton id="btnSaveStudy" value="Save" actionListener="#{studyController.createStudy()}"
                                 update=":studyform:studydt"/>
                <p:commandButton id="btnCancelStudy" value="Clear" type="reset" update=":addstudyform"/>

            </p:panelGrid>
        </h:form>
        <br/>
        <br/>
        <h:form id="studyform" style="alignment-adjust:middle">
            <p:dataTable id="studydt" value="#{studyController.retrieveStudy()}" var="item" 
                         paginator="true" rows="15" emptyMessage="No Records Found">

                <p:column filterStyleClass="filterstyle" filterBy="#{item.studyName}"
                          filterMatchMode="startsWith" style="text-align: left;">
                    <f:facet name="header"> StudyName </f:facet>
                    <h:outputText value="#{item.studyName}"/>
                </p:column>

                <p:column filterStyleClass="filterstyle" filterBy="#{item.sponsor}"
                              filterMatchMode="startsWith" style="text-align: center;">
                        <f:facet name="header"> Sponsor </f:facet>
                        <h:outputText value="#{item.sponsorName}"/>
                </p:column>                 

            </p:dataTable>
            </h:form>
    </ui:define>
    </ui:composition>
</html>

This is the perisistence.xml file

<?xml version="1.0" encoding="UTF-8"?>
<persistence version="2.0" xmlns="http://java.sun.com/xml/ns/persistence"   xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_2_0.xsd">
   <persistence-unit name="ABCPU" transaction-type="JTA">
       <jta-data-source>jdbc/ABC</jta-data-source>
       <exclude-unlisted-classes>false</exclude-unlisted-classes>           
   </persistence-unit>
 <properties>
        <property name="eclipselink.ddl-generation.output-mode" value="database"/>
        <property name="eclipselink.jdbc.batch-writing" value="Buffered"/>
        <property name="eclipselink.logging.level" value="INFO"/>
        <property name="eclipselink.ddl-generation" value="create-or-extend-tables"/>
    </properties>
</persistence>

Update

I think I am getting the error because I have added the SponsorName column in Study entity.

Can we map the columns from one entity in another?

If yes, Can some one suggest me how to do it.

Was it helpful?

Solution

It seems what you are trying to do is work how you want things displayed into the entity design, which seems like a bad idea. When you want to display things differently, you will be stuck changing the entire app.

You cannot map a field from one table/entity in another in the way you are trying. You have mapped your Sponsor entity to the sponsor table - StudyName exists in a different table so you will always get an exception reading or writing this entity. Create the entity the way you would expect to use it in the application - I don't think it makes sense to have a studyName in a Sponsor java object, or a sponsorName in a study object. Wouldn't it make more sense to have a getSponsorName that checked if there were an associated sponsor and called getName on it, rather than try to store the name in two spots?

There are many options to get fields and or entity combinations back if that is what you want. JPQL can return anything, for instance 

"SELECT s.studyId, s.studyName, sp.sponsorName, sp.address FROM Study s left join sp.sponsorId sp"

will return you a list of Object[]s containing the field values. Or 

"SELECT s, sp.sponsorName FROM Study s left join sp.sponsorId sp"

returns the list of Object[]s containing Study objects and the referenced sponsorName.

You can also use native queries and map the results using ResultSetMappings to get the same results.

OTHER TIPS

My guess is it is a case issue. Try defining your @Column annotations as all uppercase.

If you really want to use camel case, then you need to quote the columns names, i.e. @Column(name="'StudyName'").

There is also the persistence unit property, "eclipselink.jpa.uppercase-column-names"="true" that will force all column names to uppercase.

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