Three forms of JBoss for EJB QL extensions

Three forms of JBoss for EJB QL extensions

Author:sam sha
email:sam_sha@sina.com.cn
Date:2004-3-18

The EJB 2.0 specification provides a way to describe the entity Bean lookup, which is called an EJB QL. The EJB QL is similar to SQL, but it has been modified to support the EJB concept, and many features have been cut to make it easy to implement on many EJB servers.
In version 2.0, support is limited. An EJB query only supports select,from,where three clauses.
Examples: MySQL table news, followed by this table for example.
News
{
ID Int (4)
Title varchar (100)
Content text
IssueDate Date
}

EJB QL General Usage: "Select OBJECT (p) from enewscmp as P WHERE p.id =? 1"

Corresponds to the CMP entity Bean, named ENEWSCMP.

Because of the limited functionality of EJB QL, such as not even an order by, some EJB servers have expanded the EJB QL functionality.

JBoss for </