一次性向所有MySQL Select Queries添加一列 [英] Add a column to all MySQL Select Queries in a single shot

问题描述

例如，代码中的原始查询如下所示：

尝试为所有MySQL在运行时选择查询选择查询。 >

  select a，b，c from ...... 
选择x，y from ... 
  

所有这些都需要在运行时 修改为：

  select a，b，c / * Comment * / from ... 
选择x，y / * Comment * / from ... 
  

应用程序在Hibernate 4.2.1上运行。
我只能想到的解决方案是扩展 org.hibernate.dialect.MySQLDialect 并添加 / * Comment * / 在新的 CustomMySQLDialect 中。

对要修改哪种方法来完成此操作有点困惑。希望任何指向正确的方向。

Can transformSelectString（java.lang.String） method in org.hibernate.dialect.Dialect 被覆盖来完成这个任务吗？编辑1：自定义MySQL方言中的
transformSelectString不适用于运行时SQL修改

$ b

>解决方案

创建自定义数据库拦截器

  package com.felix.dao.interceptor; 
 import org.hibernate.EmptyInterceptor; 
 
 public class CustomDBInterceptor extends EmptyInterceptor {
 $ b $ @Override 
 public String onPrepareStatement（String sql）{
 String commentStr =/ * Comment * / 
返回super.onPrepareStatement（commentStr + sql）; 
 
 
 
 
 
 $ p $在Spring Context文件中，configure会话工厂的拦截器： 
 
 
 < bean id =customDBInterceptorclass =com.felix.dao.interceptor。 CustomDBInterceptor/> 
< bean id =sessionFactory
 class =org.springframework.orm.hibernate4.LocalSessionFactoryBean> 
< property name =dataSourceref =datasource/> 
< property name =entityInterceptor> 
< ref bean =customDBInterceptor/> 
< / property> 
 ... 
< / bean> 
  
确保Custom DB Interceptor对sessionFactory没有循环依赖关系。 
通过以上所述，通过会话工厂触发的所有查询都会被拦截，修改，然后传递给 onPrepareStatement 方法。
 
Trying to add a comment to all MySQL Select Queries in my web application at runtime.

For example, the original queries in the code looks like:
select a,b,c from ......
select x,y from...
All of these need to be modified at runtime to:
select a,b,c /*Comment*/ from ...
select x,y /*Comment*/ from ...
The application runs on Hibernate 4.2.1.
Only solution I can think of is extending the org.hibernate.dialect.MySQLDialect and add the /*Comment*/ in the new CustomMySQLDialect. 

A little confused on which method to modify to accomplish this. Would appreciate any pointer in the right direction.

Can transformSelectString(java.lang.String) method in org.hibernate.dialect.Dialect be overridden to accomplish this? 

EDIT 1:
transformSelectString in a Custom MySQL Dialect is not working for runtime SQL modification
解决方案
Create a Custom DB Interceptor
package com.felix.dao.interceptor;
import org.hibernate.EmptyInterceptor;

public class CustomDBInterceptor extends EmptyInterceptor {

  @Override
  public String onPrepareStatement(String sql) {
    String commentStr = "/*Comment*/"
    return super.onPrepareStatement(commentStr+sql);
  }

}
In the Spring Context file, configure the Interceptor for the session factory:
<bean id="customDBInterceptor" class="com.felix.dao.interceptor.CustomDBInterceptor"/>
<bean id="sessionFactory"
    class="org.springframework.orm.hibernate4.LocalSessionFactoryBean">
    <property name="dataSource" ref="datasource" />
    <property name="entityInterceptor">
        <ref bean="customDBInterceptor"/>
    </property>
    ...
</bean>
Make sure the Custom DB Interceptor does not have a cyclic dependency on the sessionFactory.
With the above, all queries fired through the session factory, are intercepted, modified and then passed to the onPrepareStatement method.

                        
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