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Sams Teach Yourself J2EE™ in 21 Days by Peter Roxburgh, Andy Longshaw, Debbie Law, Dan Haywood, Martin Bond

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EJB QL

By now, you should have a good idea as to how a bean's CMP fields and CMR fields are managed and persisted by the EJB container. However, there is still one area that you covered yesterday when you were learning about BMP Entity beans that has not yet been touched on today, and that is how to specify finder methods. For this, you need to know something about the EJB Query Language, or EJB QL.

EJB QL was introduced in the EJB 2.0 specification to make beans more portable across EJB containers. Previously, each EJB container vendor created their own proprietary mechanism for specifying the semantics of finder methods. This is no longer the case.

As a language, EJB QL is based on ANSI SQL, which you have seen embedded within the case study ...

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