Hereare someexamples:QCustomer customer = QCustomer.customer // delete all lete(customer).execute // delete all customers with a level less than lete(customer).where(( 3)).execute The where call is optional and the execute call performs the deletion and returns theamount of deleted entities.DML clauses in JPA don't take JPA level cascade rules into account and don't providefine-grained second level cache interaction. 2.1.11. Delete clausesDelete clauses in Querydsl JPA follow a simple delete-where-execute form. 2.1.8. General usageUse the the cascading methods of the JPQLQuery interface like thisselect:Set the projection of the query. Join usage is typesafe, and follows the following pattern:QCat cat = QCat.cat QCat mate = new QCat( 'mate') QCat kitten = new QCat( 'kitten') lectFrom(cat).innerJoin(cat.mate, mate).leftJoin(cat.kittens, kitten).fetch The native JPQL version of the query would beselect cat from Cat as catinner join cat.mate as mateleft outer join cat.kittens as kittenAnother lectFrom(cat).leftJoin(cat.kittens, kitten).on(( 10.0)).fetch With the following JPQL versionselect cat from Cat as catleft join cat.kittens as kittenon kitten.bodyWeight 10.0.
2.1.7. Using joinsQuerydsl supports the following join variants in JPQL: inner join, join, leftjoin and right join. The query paths and operations are the samein all implementations and also the Query interfaces have a common base interface.To get an impression of the expressivity of the Querydsl query and expression types go tothe javadocs and explore, .Expression. Also function/methodinvocations are constructed in a fully type-safe manner.Consistencyis another important principle.
Queries are constructed based on generated querytypes that reflect the properties of your domain types.
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