Am I missing something about createNativeQuery?

[dornus]

I'm trying to do a basic native query in MySql to see how it works.

 private Timestamp getServerTime(){
 final Query q = em.createNativeQuery(
 "select now()", Timestamp.class
 );
 return (Timestamp)q.getSingleResult();
 }

Is there a reason this doesn't work?

[STDOUT] org.hibernate.MappingException: Unknown entity: java.sql.Timestamp
 at org.hibernate.impl.SessionFactoryImpl.getEntityPersister(SessionFactoryImpl.java:648)
 at org.hibernate.loader.custom.SQLQueryReturnProcessor.getSQLLoadable(SQLQueryReturnProcessor.java:53)
 at org.hibernate.loader.custom.SQLQueryReturnProcessor.processRootReturn(SQLQueryReturnProcessor.java:119)
 at org.hibernate.loader.custom.SQLQueryReturnProcessor.processReturn(SQLQueryReturnProcessor.java:98)
 at org.hibernate.loader.custom.SQLQueryReturnProcessor.process(SQLQueryReturnProcessor.java:87)
 at org.hibernate.loader.custom.SQLCustomQuery.<init>(SQLCustomQuery.java:105)
 at org.hibernate.impl.SQLQueryImpl.list(SQLQueryImpl.java:156)
 at org.hibernate.impl.AbstractQueryImpl.uniqueResult(AbstractQueryImpl.java:650)
 at org.hibernate.ejb.QueryImpl.getSingleResult(QueryImpl.java:43)

[dornus]

I am also trying something similar with one of my par classes and not having any luck

 private MyParClass getResult(String id) {
 final Query q = em.createNativeQuery(
 "from MyParClass o " +
 "where myId = :id "+
 "and myDate + INTERVAL 24 hour >= now() ",MyParClass.class
 );
 q.setParameter("id", id);

 return (MyParClass) q.getSingleResult();
 }

[dornus]

The error for the par query is

11:08:07,144 WARN [JDBCExceptionReporter] SQL Error: 1064, SQLState: 42000
11:08:07,144 ERROR [JDBCExceptionReporter] You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the righ
t syntax to use near 'from MyParClass o where myId = '1' and myDate + INTERVAL 2' at line 1
11:08:07,159 INFO [STDOUT] org.hibernate.exception.SQLGrammarException: could not execute query
 at org.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:65)
 at org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:43)
 at org.hibernate.loader.Loader.doList(Loader.java:2150)
 at org.hibernate.loader.Loader.listIgnoreQueryCache(Loader.java:2026)
 at org.hibernate.loader.Loader.list(Loader.java:2021)
 at org.hibernate.loader.custom.CustomLoader.list(CustomLoader.java:109)
 at org.hibernate.impl.SessionImpl.listCustomQuery(SessionImpl.java:1544)
 at org.hibernate.impl.SQLQueryImpl.list(SQLQueryImpl.java:165)
 at org.hibernate.impl.AbstractQueryImpl.uniqueResult(AbstractQueryImpl.java:650)
 at org.hibernate.ejb.QueryImpl.getSingleResult(QueryImpl.java:43)

[majohnst]

For a native query, I think you have to have a fully valid SQL statement. It looks like you may be using an HQL statement " from MyClass" when it should be "select field1, field2 from MyClass".

[dornus]

Yep, you're right!

It works now.

Thanks!