java - 从 Oracle Db 切换到 MySQL。命名查询不再有效

Question

这适用于 Oracle，但我们被告知切换到 MySQL。更改驱动程序信息和其他相关设置以指向 MySQL 数据库后，我无法再执行命名查询。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")

然后我有执行查询的代码，如下所示:

query = 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 Error: 1248, SQLState: 42000

2013-04-24 10:46:00,677 ERROR [org.hibernate.util.JDBCExceptionReporter] (http-127.0.0.1-8080-1) Every derived table must have its own alias

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有一个别名，并且我可以编辑派生 SQL 以通过添加别名来使其正常工作。我的问题是这样的。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？

hibernate 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"/>

Answer 1

由于 ROWNUM 是 MySQL 中不支持的 Oracle 关键字(例如，请参阅 this question )，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。

(为后代添加答案)