Hibernate高级查询实战[1]

大家知道在Hibernate Framework中提供了三种查询数据的方式

Hibernate Query Language （HQL）

它是ANSI SQL的最小OO Dialect例

sessioncreateQuery(from Category c where cname like Laptop%);

entityManagercreateQuery(select c from Category c where cname like Laptop%);

Criteria query

它是HQL查询的延伸提供了一些高级查询功能例

sessioncreateCriteria(Categoryclass)

add( Restrictionslike(name Laptop%) );

Native SQL query :

sessioncreateSQLQuery(

select {c*} from CATEGORY {c} where NAME like Laptop%

)addEntity(c Categoryclass);

最近我在项目中经常遇到Hibernate数据查询的任务我对一些我遇到的较难的课题举例进行说明

《表述SELECT》

Criteria crit = sessioncreateCriteria(Userclass)

setProjection( ProjectionsprojectionList()

add( Projectionsproperty(lastname))

add( Projectionsproperty(firstname))

list();

《表述WHERE》

Criteria crit = sessioncreateCriteria(Userclass)

add(Restrictionseq(email foo@hibernateorg))

uniqueResult();

《表述GROUP》

Criteria crit = sessioncreateCriteria(Userclass)

setProjection( ProjectionsprojectionList()

add( ProjectionsgroupProperty(lastname))

add( ProjectionsgroupProperty(firstname))

list()

《表述ORDER》

Criteria crit = sessioncreateCriteria(Userclass)

addOrder( Orderasc(lastname) )

addOrder( Orderasc(firstname) )

list();

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