title: org.hibernate.exception.SQLGrammarException: could not insert:
body: <p>Hi Im running example using hibernate with postgresql 8.4, when i try to add it will dispay following error</p>
  
  <pre><code>org.hibernate.exception.SQLGrammarException: could not insert: [com.claystone.db.OrWorkgroup]
      at org.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:67)
      at org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:43)
      at org.hibernate.persister.entity.AbstractEntityPersister.insert(AbstractEntityPersister.java:2267)
      at org.hibernate.persister.entity.AbstractEntityPersister.insert(AbstractEntityPersister.java:2660)
      at org.hibernate.action.EntityInsertAction.execute(EntityInsertAction.java:56)
      at org.hibernate.engine.ActionQueue.execute(ActionQueue.java:250)
      at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:234)
      at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:141)
      at org.hibernate.event.def.AbstractFlushingEventListener.performExecutions(AbstractFlushingEventListener.java:298)
      at org.hibernate.event.def.DefaultFlushEventListener.onFlush(DefaultFlushEventListener.java:27)
      at org.hibernate.impl.SessionImpl.flush(SessionImpl.java:1000)
      at org.hibernate.impl.SessionImpl.managedFlush(SessionImpl.java:338)
      at org.hibernate.transaction.JDBCTransaction.commit(JDBCTransaction.java:106)
      at com.claystone.server.setup.VehicleManager.AddWorkGroup(VehicleManager.java:700)
      at com.claystone.server.setup.SetupServiceImpl.AddWorkGroup(SetupServiceImpl.java:1077)
      at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
      at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
      at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
      at java.lang.reflect.Method.invoke(Unknown Source)
      at com.google.gwt.user.server.rpc.RPC.invokeAndEncodeResponse(RPC.java:527)
      at com.google.gwt.user.server.rpc.RemoteServiceServlet.processCall(RemoteServiceServlet.java:166)
      at com.google.gwt.user.server.rpc.RemoteServiceServlet.doPost(RemoteServiceServlet.java:86)
      at javax.servlet.http.HttpServlet.service(HttpServlet.java:637)
      at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
      at org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java:487)
      at org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:362)
      at org.mortbay.jetty.security.SecurityHandler.handle(SecurityHandler.java:216)
      at org.mortbay.jetty.servlet.SessionHandler.handle(SessionHandler.java:181)
      at org.mortbay.jetty.handler.ContextHandler.handle(ContextHandler.java:729)
      at org.mortbay.jetty.webapp.WebAppContext.handle(WebAppContext.java:405)
      at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152)
      at org.mortbay.jetty.handler.RequestLogHandler.handle(RequestLogHandler.java:49)
      at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152)
      at org.mortbay.jetty.Server.handle(Server.java:324)
      at org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java:505)
      at org.mortbay.jetty.HttpConnection$RequestHandler.content(HttpConnection.java:843)
      at org.mortbay.jetty.HttpParser.parseNext(HttpParser.java:647)
      at org.mortbay.jetty.HttpParser.parseAvailable(HttpParser.java:205)
      at org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:380)
      at org.mortbay.io.nio.SelectChannelEndPoint.run(SelectChannelEndPoint.java:395)
      at org.mortbay.thread.QueuedThreadPool$PoolThread.run(QueuedThreadPool.java:488)
  Caused by: org.postgresql.util.PSQLException: ERROR: column "last_modified_time" is of type last_modified_time but expression is of type bytea
      at org.postgresql.core.v3.QueryExecutorImpl.receiveErrorResponse(QueryExecutorImpl.java:1548)
      at org.postgresql.core.v3.QueryExecutorImpl.processResults(QueryExecutorImpl.java:1316)
      at org.postgresql.core.v3.QueryExecutorImpl.execute(QueryExecutorImpl.java:191)
      at org.postgresql.jdbc2.AbstractJdbc2Statement.execute(AbstractJdbc2Statement.java:452)
      at org.postgresql.jdbc2.AbstractJdbc2Statement.executeWithFlags(AbstractJdbc2Statement.java:351)
      at org.postgresql.jdbc2.AbstractJdbc2Statement.executeUpdate(AbstractJdbc2Statement.java:305)
      at com.mchange.v2.c3p0.impl.NewProxyPreparedStatement.executeUpdate(NewProxyPreparedStatement.java:105)
      at org.hibernate.jdbc.NonBatchingBatcher.addToBatch(NonBatchingBatcher.java:23)
      at org.hibernate.persister.entity.AbstractEntityPersister.insert(AbstractEntityPersister.java:2247)
      ... 38 more
  </code></pre>
  
  <p>How to solve this error.</p>