Db4o

db4o (database for objects) was an embeddable open-source object database for Java and .NET developers. It was developed, commercially licensed and supported by Actian. In October 2014, Actian declined to continue to actively pursue and promote the commercial db4o product offering for new customers. The term object-oriented database system dates back to around 1985, though the first research developments in this area started during the mid-1970s. The first commercial object database management systems were created in the early 1990s; these added the concept of native database driven persistence into the field of object-oriented development. The second wave of growth was observed in the first decade of the 21st century, when object-oriented databases written completely in an object-oriented language appeared on the market. db4o is one of the examples of such systems written completely in Java and C#. The db4o project was started in 2000 by chief architect Carl Rosenberger, shipping in 2001. It was used in enterprise and academic applications prior to its commercial announcement in 2004 by newly created private company Db4objects Inc. In 2008 db4o was purchased by Versant corporation, which marketed it as open-source bi-licensed software: commercial and the GNU General Public License (GPL). db4o represents an object-oriented database model. One of its main goals is to provide an easy and native interface to persistence for object oriented programming languages. Development with db4o database does not require a separate data model creation, the application's class model defines the structure of the data. db4o attempts to avoid the object/relational impedance mismatch by eliminating the relational layer from a software project. db4o is written in Java and .NET and provides the respective APIs. It can run on any operating system that supports Java or .NET. It is offered under licenses including GPL, the db4o Opensource Compatibility License (dOCL), and a commercial license for use in proprietary software.