Question

我试图在我的行文上制造“搜索引擎”。

I have a table with Id, Name and Description. When I have an Id I can get the record with this Id by find(). But if I want to get records by Name or Description how can I do that? Did I ve to set the Name as index?

感谢。

Answer 1

As a general rule, if you have to frequently query a table by one of its fields and the table contains many records, it might be a good idea to create an index for that field in the database.

关于另一个问题:如果你需要以姓名、描述或由其他一些领域获得记录,以及你重新使用日本广播公司,那么就使用。例如,假定该实体为<代码>MyEntity(有id>、 姓名、>>tfscription) 下面的询问将回到一份实体名单(a)。姓名:

EntityManager em = ...         // get the entity manager
Query q = em.createQuery("SELECT me FROM MyEntity me WHERE me.name = :name");
q.setParameter("name", aName); // aName is the name you re looking for
List<MyEntity> results = (List<MyEntity>) q.getResultList();

http://docs.oracle.com/javaee/5/tutorial/doc/bnbpz.html“rel=“nofollow”>tutorial 。

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