使用 spring 数据 JPA 时添加 PARTITION 语句进行查询

Question

take the example of the below SQL query

SELECT * FROM employees PARTITION (p0) WHERE name ='John';

The above example can easily be written without "PARTITION (p0)" in Spring data JPA. It gets a lot difficult when I need to add a partition.

One possible solution is to use native SQL. But, that is not an option for me because I have to use PaginationAndSorting and Criteriabuilder. Any suggestions would be great. Thanks.

Answer 1

You can't do this with the Criteria API since it basically creates JPQL put the partition clause is part of SQL and there is no equivalent in JPQL.

Since you seem to require to create the query dynamically I'd suggest you look into Querydsl and jOOQ to see if they support the partition clause or alternatively construct the SQL yourself using String concatenation. In that case you have to take care that you don't create a SQL injection vulnerability.

If all you need is actually pagination, that can be combined with with native @Query annotations just fine.

Answer 2

I finally found a way to do this.

Need to create an interceptor to intercept all SQL queries and edit it as per requirement.

@Component
public class MyInterceptor extends EmptyInterceptor {

    private static final long serialVersionUID = 1;
    @Autowired
    @Qualifier("PartitionContext")
    private ThreadLocal<String> partitionContext;

    @Override
    public String onPrepareStatement(String sql) {
        String partition = partitionContext.get();
        if (partition != null) {
            StringBuilder sb = new StringBuilder(sql);
            sql = sb.insert(sql.indexOf(" where"), partition).toString();
            partitionContext.remove();
        }
        return super.onPrepareStatement(sql);
    }
}

We also need to register the interceptor like this.

Component
public class MyInterceptorRegistration implements HibernatePropertiesCustomizer {

    @Autowired
    private MyInterceptor myInterceptor;

    @Override
    public void customize(Map<String, Object> hibernateProperties) {
        hibernateProperties.put("hibernate.session_factory.interceptor", myInterceptor);
    }
}