0

这适用于 Oracle，但我们被告知要切换到 MySQL。在更改驱动程序信息和其他相关设置以指向 MySQL 数据库后，我不再能够执行我的命名查询。这是实体中定义的最简单的一个：

@NamedQuery(name="get_capability", query="select cb from Capability cb where cb.financial_Id = :fiId")

然后我有代码来执行查询，如下所示：

查询 = em.createNamedQuery("get_capability");

. . .

query.setParameter("fiId", fiId);

query.setMaxResults(1);

cabability = (Capability) query.getSingleResult();

最后一行抛出异常：

2013-04-24 10:46:00,677 WARN [org.hibernate.util.JDBCExceptionReporter] (http-127.0.0.1-8080-1) SQL 错误：1248，SQLState：42000

2013-04-24 10:46:00,677 错误 [org.hibernate.util.JDBCExceptionReporter] (http-127.0.0.1-8080-1) 每个派生表都必须有自己的别名

生成的 SQL 记录在日志文件中，如下所示：

/* named HQL query get_capability */ select
    * 
from
    ( select
        capability0_.FINANCIAL_ID as FINANCIAL1_272_,
        capability0_.ACTIVE_CONNECTIONS as ACTIVE2_272_,
        capability0_.ALLOWED_CONNECTIONS as ALLOWED3_272_,
        capability0_.COMPLETE_DETAILS as COMPLETE4_272_,
        capability0_.FI_NAME as FI5_272_,
        capability0_.MESSAGE_FORMAT as MESSAGE6_272_,
        capability0_.PROVIDER_ID as PROVIDER7_272_,
        capability0_.STATUS as STATUS272_,
        capability0_.SUPPORTS_ACCOUNTS as SUPPORTS9_272_,
        capability0_.SUPPORTS_CUSTOMER as SUPPORTS10_272_,
        capability0_.SUPPORTS_IMAGE as SUPPORTS11_272_,
        capability0_.SUPPORTS_STATEMENTS as SUPPORTS12_272_,
        capability0_.SUPPORTS_TRANSACTIONS as SUPPORTS13_272_,
        capability0_.SUPPORTS_TRANSFER as SUPPORTS14_272_ 
    from
        INSTITUTION capability0_ 
    where
        capability0_.FINANCIAL_ID=? ) 
where
    rownum <= ?

我已经阅读了此错误的含义，即每个派生表都需要一个别名，并且我可以编辑派生 SQL 以通过添加别名来使其工作。我的问题是这个。由于这是一个派生查询 (SQL)，我如何告诉 hibernate 添加别名，或者告诉 MySQL 不需要它？

休眠部分配置：

<property name="hibernate.dialect" value="org.hibernate.dialect.MySQLDialect" />   
<property name="hibernate.connection.driver_class" value="com.mysql.jdbc.Driver"/> 
<property name="hibernate.showSql" value="true" /> 
<property name="hibernate.format_sql" value="true"/> 
<property name="hibernate.use_sql_comments" value="true"/>
4

2 回答 2

1

因为ROWNUM是 MySQL 中不支持的 Oracle 关键字（例如，请参阅此问题），我认为 Hibernate 在构建查询时仍然以 Oracle 为目标。

验证您是否已更改为相应的 Hibernate 方言。

（为后代添加了答案）

于 2013-04-24T21:51:56.560 回答
0

您在 FROM 中的子查询是“派生表”，您必须命名该派生表。

像这样的东西应该工作

select
    RES.field1, RES.field2 
from
    ( select
        capability0_.FINANCIAL_ID as FINANCIAL1_272_,
        capability0_.ACTIVE_CONNECTIONS as ACTIVE2_272_,
        capability0_.ALLOWED_CONNECTIONS as ALLOWED3_272_,
        capability0_.COMPLETE_DETAILS as COMPLETE4_272_,
        capability0_.FI_NAME as FI5_272_,
        capability0_.MESSAGE_FORMAT as MESSAGE6_272_,
        capability0_.PROVIDER_ID as PROVIDER7_272_,
        capability0_.STATUS as STATUS272_,
        capability0_.SUPPORTS_ACCOUNTS as SUPPORTS9_272_,
        capability0_.SUPPORTS_CUSTOMER as SUPPORTS10_272_,
        capability0_.SUPPORTS_IMAGE as SUPPORTS11_272_,
        capability0_.SUPPORTS_STATEMENTS as SUPPORTS12_272_,
        capability0_.SUPPORTS_TRANSACTIONS as SUPPORTS13_272_,
        capability0_.SUPPORTS_TRANSFER as SUPPORTS14_272_ 
    from
        INSTITUTION capability0_ 
    where
        capability0_.FINANCIAL_ID=? ) **RES**
where
    rownum <= ?
于 2015-08-10T19:19:36.717 回答