Free persistence framework software for linux

Apache Cayenne project is a free object-relational persistence framework written in Java. Its goal is to make development of database Java applications faster and more consistent with the Object Oriented Programming concept.
Some of the ideas used in Cayenne have been inspired by the persistence mechanism of NeXTs (and now Apples) WebObjects application server.
Whats New in 2.0.3 Stable Release:
- This release features a number of bugfixes, including some serious synchronization issues.
- It is a recommended upgrade.
Whats New in 3.0M1 Development Release:
- This is the first milestone release of Cayenne 3.0.
- The most visible addition to Cayenne is a JSR-220 Java Persistence API Provider (a.k.a. JPA), but significant enhancements have been made to performance and flexibility.
- It is already in production within several products.

Cayenne is a powerful, full-featured Java Object Relational Mapping framework. Cayenne project is open source and completely free. One of the main Cayenne distinctions is that it comes with cross-platform modeling GUI tools.
This places Cayenne in the league of its own, making it a very attractive choice over both closed source commercial products and traditional "edit your own XML" open source solutions.
Enhancements:
- This release fixes a number of bugs in 1.2.

databeans is a fully object oriented (not relational) persistence framework for Java, based on the use of the JavaBeans accessor methods to read and write data on disk instead of in the classes instance fields.
Main features:
- based on the use of the javabeans accessor methods to read/write data on disk in place of in the classes instance fields
- distributed (through RMI)
- transactional (with the 4 ANSI isolation levels supported)
- garbage collected (backed by an on-disk heap "heapspace")
- with persistent versions of the Collection classes
Installation:
Extract the archive into any appropriate directory on your hard drive. It will create a "databeans" directory with the following contents:
build.xml
api
[api documentation as generated by javadoc]
bin
databeans_admin
databeans_admin.bat
databeans_export
databeans_export.bat
databeans_import
databeans_import.bat
export.bsh
import.bsh
mkheapspace
mkheapspace.bat
mkheapspace.bsh
docs
getting_started.txt
gpl.txt
lib
databeans_admin.jar
databeans_client.jar
databeans.jar
security
databeans.policy
sample
client
build.xml
Department.java
Employee.java
policy
Sample.java
server
build.xml
DepartmentImpl.java
Department.java
EmployeeImpl.java
Employee.java
policy
src
[java source files]
The most interesting part for now is the file getting_started.txt located in the docs/ directory. It will guide you through running a sample application (which is located in the sample/ directory). That done, go on and read the manual (below) for a complete view of the products features.

Gentle.NET is an RDBMS independent object persistence framework. Gentle.NET features automatic SQL generation and object construction, an SQL factory for creating custom queries, DataView construction helpers, excellent performance and reasonably complete docs.
The framework defines a few attributes with which you have to decorate the objects you wish to persist. Decorate classes with the TableName attribute, and members (properties and fields as you see fit) with the TableColumn attribute.
There are additional attributes available which need only be used when no Analyzer class exists for the database you are using (see Database Provider - Implementation Status). The Analyzer classes are used to obtain metadata on the current schema directly from the database, thus bypassing the need for replicating this information in your code.
If no Analyzer exists, primary key columns must be decorated with the PrimaryKey attribute, and foreign keys and their mappings must be declared using the ForeignKey attribute. The TableColumn attribute provides properties allowing you to provide details on type, size and null-handling. If an Analyzer does exist, the information obtained automatically overrides any such setting.
Business objects may optionally inherit from the Persistent class, which provides a set of standard methods for persisting and retrieving objects. You can replicate these on a different base class if needed, or on a manager class if you prefer a more SOA-oriented design. Gentle provides support for identity columns (where the database assigns a primary key value to the row being inserted) to implementors of IPersistent (which includes the Persistent class).
The main access point into the framework functionality is provided by the PersistenceBroker class, which is responsible for orchestrating all access to a given database provider.
The PersistenceBroker is responsible for basic query construction and caching, as well as interaction with the database backends. You can create as many PersistenceBroker instances as needed, such as one for every database to which you need to connect. Various classes permit or require you to pass a PersistenceBroker instance, which will be used subsequently for all database operations performed by the class.
If you need to connect to a single database only, you can use the static Broker class, which delegates all calls to a default PersistenceBroker instance (using the DefaultProvider configured in the configuration file).
Persistent objects are identified by a Key, which is really just a Hashtable with some convenient methods for gathering property values from objects. The Key class knows how to populate itself when given an object instance and a set of property names, and also provides a means of obtaining a key holding just the primary key fields.
This is useful when constructing custom queries as constraints can be passed as Key instances to methods on both the (Persistence)Broker and SqlBuilder classes. This encapsulation also enables Gentle to work with multi-column primary keys.
To execute custom SQL statements use the SqlStatement class. Use the SqlBuilder class to construct instances of this class whenever the statement is for a supported type (i.e. a class decorated with the proper attributes as outlined above).
The SqlBuilder provides a database independent way of constructing queries and has many methods for adding constraints and otherwise customizing the query. It is used internally by the PersistenceBroker whenever it needs to generate statements.
You can declare a DataView layout using the CustomView attribute on the properties to include in the DataView. The actual DataView can be obtained using the ObjectView class by supplying an array of business objects.
Multiple statements can be transacted (grouped) using the Transaction class.
Enhancements:
- This release features a complete rewrite of the cache subsystem, with significant performance improvements as a result.
- There have also been several minor improvements and bugfixes throughout the code base.

TTraq provides a timesheet and time tracking system.
TTraq is a time tracking (timesheet) system that helps consultants, employees, freelancers, or service providers of any kind who work in a project oriented environment.
It is a sophisticated Web application based upon the Struts framework by the Apache Group. It is easy to set up and very quickly accessible. The data is managed via the Hibernate persistence framework.
It should run on any J2EE compliant container. All data can be exported to CSV, HTML, or Excel. A backing store (database) is included in the distribution.
I18N is fully supported by resource properties. Currently available languages are English and German, but this can easily extended in a approbiate resource file.
TTraq is organized in following main classes:
.User (Standard, Project Manager, Administrators)
.Project
.Timestamp
Enhancements:
- This is a bugfix release for not creating the default admin user.

Xmldoom package contains the XML Document Object-Oriented Model.

Xmldoom is what is commonly refered to as an Object Persistence Framework or an Object-Relational Mapping [1]. Basically, it is a framework that allows you to create an automatic mapping between the tables in your relational database and the code objects you use to manipulate it. Any large database bound application will eventually create a code abstraction over the database as opposed to writting SQL manually for every database access. Xmldoom does this automatically and makes it possible to avoid writting any SQL.

This is not a new concept, however, there are a few things that make Xmldoom unique:

Programming language agnostic

This implementation is a Perl module. However, there exists an actively maintained JavaScript and an inactive Python implementation. This means you can setup your object and database definitions once, and be able to access your database via Xmldoom with roughly the same interface from any programming language that has an Xmldoom implementation.

Heavy abstraction

While the standard in the Perl world is to be as light as possible, Xmldoom is a heavy abstraction, and we treat that as an advantage in this context. The objects provided by Xmldoom have a very consistant and well thought-out interface, that attempts to handle as many possible "object-like" interactions as possible. The thinking is that the more Xmldoom does for you, the less you have to do. This is provided in an extensible object-oriented fashion.

Adapts to your database

Even though it is a very heavy abstraction, it doesnt hide the database from you, or force your database to operate in some set way. It can be made to adapt to almost any way you have set up your database to operate, and still provide the same consistant object interface regardless.

Object meta-data

Aside from simply connecting your database to objects, it allows you specify domain specific meta-data about each object and each of its properties. This meta-data is available anywhere in code, such that you can provide generic functions that can take any object, and perform some action on it based on the stored meta-data, without regard to the actual type of the object. For example, you can create a generic mechanism to generate reports, which can generate a report for any object, without needing to be special cased for each type of object you want to report on.

Flexible searches

Xmldoom provides you with a mechanism to search for any object based on any property, whether its a property of that object or any other, so long as it can find a keys relating the objects together. This allows to find any information in your database, without ever having to write an SQL.

cheapskate is a simple Ruby on Rails application for personal budgeting.

Rails is a web-application and persistence framework that includes everything needed to create database-backed web-applications according to the Model-View-Control pattern of separation. This pattern splits the view (also called the presentation) into "dumb" templates that are primarily responsible for inserting pre-built data in between HTML tags. The model contains the
"smart" domain objects (such as Account, Product, Person, Post) that holds all the business logic and knows how to persist themselves to a database. The controller handles the incoming requests (such as Save New Account, Update Product, Show Post) by manipulating the model and directing data to the view.

In Rails, the model is handled by whats called an object-relational mapping layer entitled Active Record. This layer allows you to present the data from database rows as objects and embellish these data objects with business logic methods. You can read more about Active Record in
link:files/vendor/rails/activerecord/README.html.

The controller and view are handled by the Action Pack, which handles both layers by its two parts: Action View and Action Controller. These two layers are bundled in a single package due to their heavy interdependence. This is unlike the relationship between the Active Record and Action Pack that is much more separate. Each of these packages can be used independently outside of Rails. You can read more about Action Pack in link:files/vendor/rails/actionpack/README.html.