Querydsl

Querydsl is a framework which enables the construction of type-safe SQL-like queries. Instead of writing queries as inline strings or externalizing them into XML files they aren be constructed via a fluent API like Querydsl.

The benefits of using a fluent API in comparison to simple strings are:

 * code completion in IDE (all properties, methods and operations can be expanded in your favorite Java IDE)
 * almost no syntactically invalid queries allowed (type-safe on all levels)
 * domain types and properties can be referenced safely (no Strings involved!)
 * adopts better to refactoring changes in domain types
 * incremental Query definition is easier

Supported backends

JPA / Hibernate

 * Getting started with Querydsl using Hibernate
 * via the querydsl-hql module
 * tested with Hibernate using Derby, HSQLDB and MySQL

JDO

 * Getting started with Querydsl using JDO
 * via the querydsl-jdoql module
 * tested with DataNucleus Access Platform

Java Collections

 * Getting started using Querydsl for Collections
 * via the querydsl-collections module

SQL

 * Getting started using Querydsl for SQL
 * via the querydsl-sql module
 * supports Derby, HSQLDB, MySQL (5.1), Postgres (8.4), Oracle (10/11) and MS SQL Server (2008)

RDF

 * via RDFBean, our Object/RDF persistence framework
 * tested with RDFBean using Sesame

Lucene

 * Getting started using Querydsl for Lucene
 * via the querydsl-lucene module

Hibernate Search

 * Getting started using Querydsl for Hibernate Search
 * via the querydsl-hibernate-search module

What is new in this release:

• Test with EclipseLink JPA
• Generics fail using JPAAnnotationProcessor
• Enums in HQL contains
• UNION ALL support
• Support custom row-mapping projections
• Scala source generation issue with column named type
• Add OSGi metadata to Querydsl modules
• Q-Type for @Embeddable in foreigen package is not created
• Query utils
• apt plugin does not cooperate with others well
• Constructor generated by query projection ignores primitives
• com.mysema.query.apt.jpa.JPAAnnotationProcess... of beta5 apt-one-jar.jar

What is new in version 2.1.0:

• Add common Factory class for FactoryExpression creation
• Add field access to QBean
• LuceneQuery.list() throws an IllegalArgumentException from Lucene if nDocs is 0

What is new in version 2.0.0:

• Scala support was added.
• Eclipse IDE support was improved.
• Initial Mongodb support was added.
• The Expression model was improved.

What is new in version 1.9.5:

• Bean generation and foreign key issues were improved.
• Bean generation annotation usage was improved.

What is new in version 1.9.0:

• No-arg methods are now cached in Q-types.
• PEntity is no longer used for embeddable Q-types.
• QueryMetadata was made serializable.
• For JPA, constructor projection doesn't always work.
• For SQL, there is generic access to schema metadata in Q-types, and support was added for special options in DML clauses.
• The reference documentation was restructured.

What is new in version 1.8.5:

• This version prevents using non-root alias paths in joins.
• Foreign key code generation has been improved improved.
• JDO supports FetchPlan modification via query.

What is new in version 1.8.0:

• A consistent DML signature, union for subqueries, query extension support, and support for DDL clauses were added.