What is Torque?
Apache Torque is an object-relational mapper for java. In other words, Torque
lets you access and manipulate data in a relational database
using java objects.
Unlike most other object-relational mappers, Torque does not use
reflection to access user-provided classes, but it generates the
necessary classes (including the Data Objects) from an XML schema
describing the database layout (which can either be written by hand
or generated from an existing database).
The XML schema can also be used to generate and execute a SQL script
which creates all the tables in the database.
As Torque hides database-specific implementation details,
Torque makes an application independent of a specific database
if no exotic features of the database are used.
Usage of autogeneration eases the customization of the database layer,
as you can override the autogenerated methods and thus easily change
their behaviour.
Torque was developed as part of the
Turbine Framework.
It is now decoupled and can be used by itself. Starting with version
2.2 Turbine uses the decoupled Torque.
Elements of Torque
Torque consists of multiple parts:
- runtime
-
The Torque runtime contains everything to allow an
application to access the database. It is the only component of Torque
needed in your application and can be used standalone.
- generator
-
The generator contains ant tasks which do all the work for the
Maven plugin. If you use the Maven plugin, you do not need to use the
generator directly.
However, the generator can also be invoked directly using ant.
- maven-plugin
-
The Maven plugin creates the O/R peer and object classes for accessing
and storing data from the database. It can also generate the XML
description of an existing database and (in reverse) create an SQL
script to create the tables in the database. Internally,
the Maven plugin uses the generator to accomplish these tasks.
- templates
-
The templates contain the building blocks used by the generator
to create the O/R peer and object classes, SQL scripts and the like.
You can change the templates if you want to customize the output
of the generator (this is only necessary in very special
circumstances).
Up to release 3.1.x, the templates were a part of the generator.
Starting with the 3.2 release of Torque, the templates have been
separated into their own jar archive.
- village
-
Village is a 100% Pure Java API that sits on top of the JDBC
API. The purpose of this API is to make it easier to interact with
a JDBC compliant relational database.
Releases
-
Most recent production release of Torque is Torque 3.3
-
Most recent production release of the Village component of Torque is Village 3.3.1
-
Most recent development release of Torque is Torque 4.0-beta1
The Apache Software Foundation
Torque is an Apache project,
and is part of a larger community of developers and users.
Apache Torque, Torque, Apache, the Apache feather logo,
and the Apache Torque project logo are trademarks of
The Apache Software Foundation.
