Question

当我执行以下代码时：

String sqlQuery = "SELECT {msg.*},  {cmd.*} " +
    "FROM schemaName.Messages AS msg " +
    "LEFT OUTER JOIN schemaName.send_commands AS cmd " +
    " ON cmd.message_key = msg.unique_key " +
    " AND ( cmd.priority = 1 ) " +
    "WHERE msg.sequence_received < 10";

Query query = session.createSQLQuery( sqlQuery )
          .addEntity( "msg",Messages.class )
          .addJoin( "cmd","msg.commands" )
          .addJoin( "msg", "cmd.message" );
query.setResultTransformer( Criteria.DISTINCT_ROOT_ENTITY );

我获取了正确的resultSet：加载了所有消息，并加载了一些SendCommands，使得msg.getCommands()不会发出额外的SQL查询。因此，我需要的所有信息都已被提取并正确映射。

但是，我遇到以下代码的问题：

Criteria crit = session.createCriteria( Messages.class )
     .add( Restrictions.lt( "sequenceReceived", Long.valueOf( 10 )) )
     .setFetchMode( "commands", FetchMode.JOIN )
     .createAlias( "commands", "cmd", Criteria.LEFT_JOIN, Restrictions.eq( "cmd.priority", 1 ) )          
     .setResultTransformer( Criteria.DISTINCT_ROOT_ENTITY );

，hibernate设法生成正确的SQL代码：

SELECT  [...]
FROM schemaName.Messages AS msg LEFT OUTER JOIN schemaName.send_commands AS cmd  
ON cmd.message_key = msg.unique_key  AND ( cmd.priority = 1 ) 
WHERE msg.sequence_received < 10

问题在于，当我尝试使用msg.getCommands()时，Hibernate会发出一个新的SQL查询并获取与给定Message关联的sendCommands。有没有办法修复映射，或者有实际的Eager Fetch？

Criteria的Hibernate映射问题

0 个答案: