Question

I’m trying to set up a small working sample of Hibernate that I found here However when I run the code I get the follwing error

Exception in thread "main" org.hibernate.exception.SQLGrammarException: could not insert: [com.sample.Person]
at org.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:92)
at org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:66)
at org.hibernate.id.insert.AbstractReturningDelegate.performInsert(AbstractReturningDelegate.java:64)
at org.hibernate.persister.entity.AbstractEntityPersister.insert(AbstractEntityPersister.java:2345)
at org.hibernate.persister.entity.AbstractEntityPersister.insert(AbstractEntityPersister.java:2852)
at org.hibernate.action.EntityIdentityInsertAction.execute(EntityIdentityInsertAction.java:71)
at org.hibernate.engine.ActionQueue.execute(ActionQueue.java:273)
at org.hibernate.event.def.AbstractSaveEventListener.performSaveOrReplicate(AbstractSaveEventListener.java:320)
at org.hibernate.event.def.AbstractSaveEventListener.performSave(AbstractSaveEventListener.java:203)
at org.hibernate.event.def.AbstractSaveEventListener.saveWithGeneratedId(AbstractSaveEventListener.java:129)
at .....


Caused by: org.postgresql.util.PSQLException: ERROR: relation "person" does not exist
Position: 13
at org.postgresql.core.v3.QueryExecutorImpl.receiveErrorResponse(QueryExecutorImpl.java:2102)
at org.postgresql.core.v3.QueryExecutorImpl.processResults(QueryExecutorImpl.java:1835)
at org.postgresql.core.v3.QueryExecutorImpl.execute(QueryExecutorImpl.java:257)
at org.postgresql.jdbc2.AbstractJdbc2Statement.execute(AbstractJdbc2Statement.java:500)
at org.postgresql.jdbc2.AbstractJdbc2Statement.executeWithFlags(AbstractJdbc2Statement.java:388)
at org.postgresql.jdbc2.AbstractJdbc2Statement.executeUpdate(AbstractJdbc2Statement.java:334)
at org.hibernate.id.IdentityGenerator$GetGeneratedKeysDelegate.executeAndExtract(IdentityGenerator.java:94)
at org.hibernate.id.insert.AbstractReturningDelegate.performInsert(AbstractReturningDelegate.java:57)
... 23 more

But I already have a table by the name person in the database and here’s my modified hibernate.cfg.xml

    <!-- hibernate dialect -->
    <property name="hibernate.dialect">org.hibernate.dialect.MySQLInnoDBDialect</property>


    <property name="hibernate.connection.driver_class">org.postgresql.Driver</property>
    <property name="hibernate.connection.url">jdbc:postgresql://localhost/testDB</property>
    <property name="hibernate.connection.username">postgres</property>
    <property name="hibernate.connection.password"></property>
    <property name="hibernate.show.sql" ></property> 
    <property name="transaction.factory_class">org.hibernate.transaction.JDBCTransactionFactory</property>

    <!-- Automatic schema creation (begin) === -->
    <property name="hibernate.hbm2ddl.auto">create</property>


    <!-- Simple memory-only cache -->
    <property name="hibernate.cache.provider_class">org.hibernate.cache.HashtableCacheProvider</property>

    <!-- Enable Hibernate's automatic session context management -->
    <property name="current_session_context_class">thread</property>

    <!-- ############################################ -->
    <!-- # mapping files with external dependencies # -->
    <!-- ############################################ -->

    <mapping resource="com/sample/Person.hbm.xml" />

</session-factory>

It would be great if anyone could point out what Im doing wrong, as this is my first attempt at Hibernate.
Thanks!

EDIT: Person.hbm.xml

<class name="com.sample.Person" table="person">

    <id name="id" column="ID">
        <generator class="native" />
    </id>

    <property name="name">
        <column name="NAME" length="16" not-null="true" />
    </property>

    <property name="surname">
        <column name="SURNAME" length="16" not-null="true" />
    </property>

    <property name="address">
        <column name="ADDRESS" length="16" not-null="true" />
    </property>

</class>

EDIT-II: Content of the log file (Postgresql.log)

 2012-02-13 09:23:25 IST LOG:  database system was shut down at 2012-02-10 18:14:57 IST
 2012-02-13 09:23:25 IST FATAL:  the database system is starting up
 2012-02-13 09:23:33 IST LOG:  database system is ready to accept connections
 2012-02-13 09:23:38 IST LOG:  autovacuum launcher started
 2012-02-13 09:46:01 IST ERROR:  syntax error at or near "auto_increment" at character 41
    2012-02-13 09:46:01 IST STATEMENT:  create table person (ID bigint not null         auto_increment, NAME varchar(16) not null, SURNAME varchar(16) not null, ADDRESS varchar(16) not null, primary key (ID)) type=InnoDB
 2012-02-13 09:46:01 IST ERROR:  relation "person" does not exist at character 13
2012-02-13 09:46:01 IST STATEMENT:  insert into person (NAME, SURNAME, ADDRESS) values   ($1, $2, $3) RETURNING *
2012-02-13 09:46:01 IST LOG:  could not receive data from client: No connection could be made because the target machine actively refused it.


2012-02-13 09:46:01 IST LOG:  unexpected EOF on client connection
2012-02-13 09:48:15 IST ERROR:  syntax error at or near "auto_increment" at character 41
2012-02-13 09:48:15 IST STATEMENT:  create table person (ID bigint not null auto_increment, NAME varchar(16) not null, SURNAME varchar(16) not null, ADDRESS varchar(16) not null, primary key (ID)) type=InnoDB
2012-02-13 09:48:15 IST ERROR:  relation "person" does not exist at character 13
2012-02-13 09:48:15 IST STATEMENT:  insert into person (NAME, SURNAME, ADDRESS) values ($1, $2, $3) RETURNING *
 2012-02-13 09:48:15 IST LOG:  could not receive data from client: No connection could be made because the target machine actively refused it.


2012-02-13 09:48:15 IST LOG:  unexpected EOF on client connection

UPDATE: I just noticed something weird, I create the relation in the DB and then run this piece of code, only to see that the table gets deleted as in it just dissapears when I run this code; any idea why this happens?

Answer 1

I solved the error by modifying the following property in hibernate.cfg.xml

  <property name="hibernate.hbm2ddl.auto">validate</property>

Earlier, the table was getting deleted each time I ran the program and now it doesnt, as hibernate only validates the schema and does not affect changes to it.