EJB QL

EJB QL or EJB -QL (Enterprise JavaBeans Query Language) is a query language for Enterprise JavaBeans ( EJB). It is used in J2EE applications. Compared to SQL, it is less complex, but also not so powerful.

History

In particular, EJB3 -QL was affected by the query language of Hibernate, Hibernate Query Language HQL.

Differences to SQL

The syntax of EJB QL is similar to SQL. However, the queries used are different from the relational language SQL, which are based on the relational model. EJB QL is used instead, the so-called " abstract schema " of the Enterprise Java Beans. An SQL query contains tables and their rows and columns. In contrast, the EJB -QL queries EJBs, and their persistent states and relations include. The result of an SQL query are lines with a fixed number of columns. The result of an EJB QL query are objects of a particular class or a collection of values ​​retrieved from a CMP field.

Swell

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