JPA Mapping Exception

[Joe San]

Guys,

I have a simple JPA mapping to a couple of tables via the XML config file. However, during startup, I get the following errors:

Caused by: org.xml.sax.SAXParseException: cvc-complex-type.2.4.a: Invalid content was found starting with element 'basic'. One of '{"http://java.sun.com/xml/ns/persistenc
e/orm":many-to-one, "http://java.sun.com/xml/ns/persistence/orm":one-to-many, "http://java.sun.com/xml/ns/persistence/orm":one-to-one, "http://java.sun.com/xml/ns/persist
ence/orm":many-to-many, "http://java.sun.com/xml/ns/persistence/orm":embedded, "http://java.sun.com/xml/ns/persistence/orm":transient}' is expected.
        at com.sun.org.apache.xerces.internal.util.ErrorHandlerWrapper.createSAXParseException(ErrorHandlerWrapper.java:195)
        at com.sun.org.apache.xerces.internal.util.ErrorHandlerWrapper.error(ErrorHandlerWrapper.java:131)
        at com.sun.org.apache.xerces.internal.impl.XMLErrorReporter.reportError(XMLErrorReporter.java:384)
        at com.sun.org.apache.xerces.internal.impl.XMLErrorReporter.reportError(XMLErrorReporter.java:318)
        at com.sun.org.apache.xerces.internal.impl.xs.XMLSchemaValidator$XSIErrorReporter.reportError(XMLSchemaValidator.java:417)
        at com.sun.org.apache.xerces.internal.impl.xs.XMLSchemaValidator.reportSchemaError(XMLSchemaValidator.java:3182)
        at com.sun.org.apache.xerces.internal.impl.xs.XMLSchemaValidator.handleStartElement(XMLSchemaValidator.java:1806)
        at com.sun.org.apache.xerces.internal.impl.xs.XMLSchemaValidator.startElement(XMLSchemaValidator.java:705)
        at com.sun.org.apache.xerces.internal.impl.XMLNSDocumentScannerImpl.scanStartElement(XMLNSDocumentScannerImpl.java:400)
        at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl$FragmentContentDriver.next(XMLDocumentFragmentScannerImpl.java:2755)
        at com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl.next(XMLDocumentScannerImpl.java:648)
        at com.sun.org.apache.xerces.internal.impl.XMLNSDocumentScannerImpl.next(XMLNSDocumentScannerImpl.java:140)
        at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanDocument(XMLDocumentFragmentScannerImpl.java:511)
        at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:808)
        at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:737)
        at com.sun.org.apache.xerces.internal.parsers.XMLParser.parse(XMLParser.java:119)
        at com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.parse(AbstractSAXParser.java:1205)
        at com.sun.org.apache.xerces.internal.jaxp.SAXParserImpl$JAXPSAXParser.parse(SAXParserImpl.java:522)
        at org.dom4j.io.SAXReader.read(SAXReader.java:465)
        at org.dom4j.io.SAXReader.read(SAXReader.java:343)
        at org.hibernate.ejb.Ejb3Configuration.addXMLEntities(Ejb3Configuration.java:712)
        ... 55 more

Below is how my mapping looks like: A Question has many Answers:

	<entity class="Question">
		<table />
		<attributes>
		  <id name="questionId">
			<generated-value strategy="SEQUENCE" generator="questionSeq"/>
			<sequence-generator name="questionSeq" sequence-name="quizSeq"/>
		  </id>
		  <basic name="examId">
			<column name="exam_id" length="10"/>
		  </basic>
		  <basic name="questionText">
		    <column name="question_text" length="4000"/>
		  </basic>
		  <basic name="questionType">
		    <column name="question_type" length="1"/>		  
		  </basic>
		  <basic name="isActive">
		    <column name="active_yn" length="1"/>		  
		  </basic>
		  <basic name="technologyId">
		    <column name="technology_id" length="10"/>		  
		  </basic>
		  <basic name="difficultyLevel">
		    <column name="difficulty_level" length="10"/>		  
		  </basic>
		  <basic name="createDate">
		    <column name="create_date" length="100"/>		  
		  </basic>
		  <basic name="author">
		    <column name="author" length="10"/>		  
		  </basic>
		  <basic name="answerCount">
		    <column name="answer_count" length="10"/>		  
		  </basic>
		  <one-to-many name="answers" mapped-by="answerId">
			<order-by/>
		  </one-to-many>		  
		</attributes>
	</entity>
	
	<entity class="Answer">
		<table />
		<attributes>
		  <id name="answerId">
		  	<column name="answer_id"/>
			<generated-value strategy="SEQUENCE" generator="answerSeq"/>
			<sequence-generator name="answerSeq" sequence-name="quizSeq"/>
		  </id>
		  <many-to-one name="question"/>
		  <basic name="answerText">
		    <column name="answer_text" length="4000"/>
		  </basic>
		  <basic name="correctAnswerYN">
		    <column name="correct_answer_yn" length="1"/>		  
		  </basic>
		  <basic name="answerDescription">
		    <column name="answer_description" length="4000"/>		  
		  </basic>
		</attributes>		
	</entity>

What is the mistake here?

[Joe San]

Modified the definitions like below:

	<entity class="Question">
		<table />
		<attributes>
		  <id name="questionId">
			<generated-value strategy="SEQUENCE" generator="questionSeq"/>
			<sequence-generator name="questionSeq" sequence-name="quizSeq"/>
			<one-to-many name="answers" target-entity="com.quintilis31.home.common.repository.common.Answer" mapped-by="question"/>
		  </id>
		  <basic name="examId">
			<column name="exam_id" length="10"/>
		  </basic>
		  <basic name="questionText">
		    <column name="question_text" length="4000"/>
		  </basic>
		  <basic name="questionType">
		    <column name="question_type" length="1"/>		  
		  </basic>
		  <basic name="isActive">
		    <column name="active_yn" length="1"/>		  
		  </basic>
		  <basic name="technologyId">
		    <column name="technology_id" length="10"/>		  
		  </basic>
		  <basic name="difficultyLevel">
		    <column name="difficulty_level" length="10"/>		  
		  </basic>
		  <basic name="createDate">
		    <column name="create_date" length="100"/>		  
		  </basic>
		  <basic name="author">
		    <column name="author" length="10"/>		  
		  </basic>
		  <basic name="answerCount">
		    <column name="answer_count" length="10"/>		  
		  </basic>		  
		</attributes>
	</entity>
	
	<entity class="Answer">
		<table />
		<attributes>
		  <id name="answerId">
		  	<column name="answer_id"/>
			<generated-value strategy="SEQUENCE" generator="answerSeq"/>
			<sequence-generator name="answerSeq" sequence-name="quizSeq"/>
        	<many-to-one name="question" fetch="LAZY">
           	  <join-column name="question_id"/>
        	</many-to-one>			
		  </id>
		  <basic name="answerText">
		    <column name="answer_text" length="4000"/>
		  </basic>
		  <basic name="correctAnswerYN">
		    <column name="correct_answer_yn" length="1"/>		  
		  </basic>
		  <basic name="answerDescription">
		    <column name="answer_description" length="4000"/>		  
		  </basic>
		</attributes>		
	</entity>

And following is the exception:

Caused by: org.xml.sax.SAXParseException: cvc-complex-type.2.4.d: Invalid content was found starting with element 'one-to-many'. No child element is expected at this poin
t.
        at com.sun.org.apache.xerces.internal.util.ErrorHandlerWrapper.createSAXParseException(ErrorHandlerWrapper.java:195)
        at com.sun.org.apache.xerces.internal.util.ErrorHandlerWrapper.error(ErrorHandlerWrapper.java:131)
        at com.sun.org.apache.xerces.internal.impl.XMLErrorReporter.reportError(XMLErrorReporter.java:384)
        at com.sun.org.apache.xerces.internal.impl.XMLErrorReporter.reportError(XMLErrorReporter.java:318)
        at com.sun.org.apache.xerces.internal.impl.xs.XMLSchemaValidator$XSIErrorReporter.reportError(XMLSchemaValidator.java:417)
        at com.sun.org.apache.xerces.internal.impl.xs.XMLSchemaValidator.reportSchemaError(XMLSchemaValidator.java:3182)
        at com.sun.org.apache.xerces.internal.impl.xs.XMLSchemaValidator.handleStartElement(XMLSchemaValidator.java:1810)
        at com.sun.org.apache.xerces.internal.impl.xs.XMLSchemaValidator.emptyElement(XMLSchemaValidator.java:725)
        at com.sun.org.apache.xerces.internal.impl.XMLNSDocumentScannerImpl.scanStartElement(XMLNSDocumentScannerImpl.java:377)
        at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl$FragmentContentDriver.next(XMLDocumentFragmentScannerImpl.java:2755)
        at com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl.next(XMLDocumentScannerImpl.java:648)
        at com.sun.org.apache.xerces.internal.impl.XMLNSDocumentScannerImpl.next(XMLNSDocumentScannerImpl.java:140)
        at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanDocument(XMLDocumentFragmentScannerImpl.java:511)
        at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:808)
        at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:737)
        at com.sun.org.apache.xerces.internal.parsers.XMLParser.parse(XMLParser.java:119)
        at com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.parse(AbstractSAXParser.java:1205)
        at com.sun.org.apache.xerces.internal.jaxp.SAXParserImpl$JAXPSAXParser.parse(SAXParserImpl.java:522)
        at org.dom4j.io.SAXReader.read(SAXReader.java:465)
        at org.dom4j.io.SAXReader.read(SAXReader.java:343)
        at org.hibernate.ejb.Ejb3Configuration.addXMLEntities(Ejb3Configuration.java:712)
        ... 55 more

[Joe San]

Obviously no reason why Annotation mapping makes life easier.

[Tamas Polgar]

Hi,
using hibernate as jpa2 provider could produce wierd situations

For your first problem:
If you change the order of your attribute mappings in Answer, and put <many-to-one name="question"/> to the last statement, it should pass the XMLSchemaValidation. It shouldnt be a problem with a jpa2 provider, but with hibernate, it is.
You use <one-to-many name="answers" mapped-by="answerId"> in your Question, this should be mapped by an attribute with Question type, with many-to-one relation type.

For your second problem

           <id name="questionId">  
             <generated-value strategy="SEQUENCE" generator="questionSeq"/>  
             <sequence-generator name="questionSeq" sequence-name="quizSeq"/>  
             <one-to-many name="answers" target-entity="com.quintilis31.home.common.repository.common.Answer" mapped-by="question"/>  
           </id>  

and

           <id name="answerId">  
             <column name="answer_id"/>  
             <generated-value strategy="SEQUENCE" generator="answerSeq"/>  
             <sequence-generator name="answerSeq" sequence-name="quizSeq"/>  
             <many-to-one name="question" fetch="LAZY">  
               <join-column name="question_id"/>  
             </many-to-one>              
           </id>  

are not good, you cannot use one-to-many or many-to-one in the id tag.
Try to put them outside the id, and sculp it a bit

How does the datamodel look like?

[Joe San]

The data model is quite simple. A Question has many Answers and it is a simple One-To-Many bidirectional relationship.

In my first post above, I had the Ont-To-Many definition outside of the id attribute and it did not work either.

[Joe San]

Seems like I have to change to Annotation mapping as this is not moving any further with my development.

[Joe San]

Tried to get rid of all the mapping errors. But now getting an all together new exception....

Caused by: org.hibernate.MappingException: Could not instantiate id generator [entity-name=com.quintilis31.home.common.repository.common.Technology]
        at org.hibernate.id.factory.DefaultIdentifierGeneratorFactory.createIdentifierGenerator(DefaultIdentifierGeneratorFactory.java:117)
        at org.hibernate.mapping.SimpleValue.createIdentifierGenerator(SimpleValue.java:177)
        at org.hibernate.impl.SessionFactoryImpl.<init>(SessionFactoryImpl.java:257)
        at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1385)
        at org.hibernate.cfg.AnnotationConfiguration.buildSessionFactory(AnnotationConfiguration.java:954)
        at org.hibernate.ejb.Ejb3Configuration.buildEntityManagerFactory(Ejb3Configuration.java:883)
        ... 54 more

Where Technology is an Entity as defined below:

	<entity class="Technology">
		<table />
		<attributes>
		  <id name="technologyId">
		  	<column name="answer_id"/>
			<generated-value strategy="SEQUENCE" generator="answerSeq"/>
			<sequence-generator name="answerSeq" sequence-name="quizSeq"/>
		  </id>
		  <basic name="technologyName">
			<column name="technology_name" length="50"/>
		  </basic>
		  <basic name="version">
		    <column name="answer_text" length="4000"/>
		  </basic>
		  <basic name="createDate">
		    <column name="create_date" length="1"/>		  
		  </basic>
		  <basic name="updateDate">
		    <column name="update_date" length="4000"/>		  
		  </basic>
		</attributes>		
	</entity>

Are sequences not supported in MySQL database?

[Tamas Polgar]

There are no sequences in mysql,
you can use id generation (when you insert the record, it generates an id, dont use it for complex relationships), or table generator which is quite cool (details).

so I created a simple version of your stuff
Answer:

package entity;

public class Answer {
    private Integer id;
    private Question question;
    private String other;
    
    public Integer getId() {
        return id;
    }
    public void setId(Integer id) {
        this.id = id;
    }
    public Question getQuestion() {
        return question;
    }
    public void setQuestion(Question question) {
        this.question = question;
    }
    public String getOther() {
        return other;
    }
    public void setOther(String other) {
        this.other = other;
    }
}

xml for it:
<entity class="entity.Answer" access="PROPERTY"> <attributes> <id name="id"> <generated-value generator="answerIdGenerator" strategy="TABLE" /> <table-generator name="answerIdGenerator" table="ID_GENERATOR" pk-column-value="Answer" pk-column-name="GENERATOR_NAME" value-column-name="NEXT_VAL" /> </id> <many-to-one name="question"/> </attributes> </entity>
Question

package entity;

import java.util.Collection;

public class Question {
    private Integer id;
    private Collection<Answer> answers;
    private String other;
    
    public Integer getId() {
        return id;
    }
    public void setId(Integer id) {
        this.id = id;
    }
    public Collection<Answer> getAnswers() {
        return answers;
    }
    public void setAnswers(Collection<Answer> answers) {
        this.answers = answers;
    }
    public String getOther() {
        return other;
    }
    public void setOther(String other) {
        this.other = other;
    }
}

xml:
<entity class="entity.Question" access="PROPERTY"> <attributes> <id name="id"> <generated-value generator="questionIdGenerator" strategy="TABLE" /> <table-generator name="questionIdGenerator" table="ID_GENERATOR" pk-column-value="Question" pk-column-name="GENERATOR_NAME" value-column-name="NEXT_VAL" /> </id> <one-to-many name="answers" mapped-by="question" /> </attributes> </entity>
sql script:
CREATE TABLE ID_GENERATOR (GENERATOR_NAME VARCHAR(50) PRIMARY KEY, NEXT_VAL INTEGER); INSERT INTO ID_GENERATOR (GENERATOR_NAME, NEXT_VAL) VALUES ('Answer', 1); INSERT INTO ID_GENERATOR (GENERATOR_NAME, NEXT_VAL) VALUES ('Question', 1); CREATE TABLE Question (ID INTEGER PRIMARY KEY, OTHER VARCHAR(4000)); CREATE TABLE Answer (ID INTEGER PRIMARY KEY, OTHER VARCHAR(4000), QUESTION_ID INTEGER);
It works for me, with hibernate as well.
Note:
many-to-one and one-to-many are the last elements of the mappings. with hibernate it seems to be required..
You dont need to use basic if you use default values (other attribute = other column). Try to use default values, it can reduce the code, and improves the readability.

you can use annotation or xml, or both. you can specify the same mapping with xml and annotations (in theory ).
however annotations could be easier to understand how jpa works.

[Joe San]

Thanks for the post. It deploys fine now.