Object databases first started to appear in 1985 and they are also known as object-oriented database management systems. The data in such databases is stored in the form of objects, as used by object-oriented programming. They are different from relational or graph databases and most of them offer a query language that allows object to be found with a declarative programming approach.
Db4o is the open source object database that is supported by a large community. The database allows .Net and Java and developers to store and recover any application object with just 1 line of code. Versant, the developer of Db4o offers a free and commercialized suite.
PicoLisp is a Lisp dialect running on Linux and it features a database functionality. First class objects are loaded from database files automatically when they are accessed and written back when modified. PicoLisp was developed in 1988 and in 2012 a Java version was created.
FramerD, developed in 2005, allows computerized creation, access and manipulation of descriptions and systems of descriptions. It is a portable distributed object-oriented database and was developed to support sharing and maintaining knowledge bases. It is optimized for pointer-intensive data structure.
Siaqodb is a NoSQL object database running on among others .NET, Unity3D as well as the Windows Phone. Thanks to the Sync Framework provider, siaqodb is a cross-platform client-side database. It can be kept in sync with server-side databases. LINQ is the query engine and it provides a LINQ query editor in the application.
McObject developed Perst, an open source object-oriented embedded database sytem (ODBMS). Data is stored in Java directly and it is available for .NET framework applications as well. Users can store, sort and retrieve objects in high-speed and with memory usages being low. It is reliable to use and offers different development tools.
Starcounter is a transactional database made available for modern commodity computers. Transactions are secured on disk and it supports duplication and full recovery. It integrates Virtual Machine and a Database Management System. It offers a .NET object API and SQL query support and gives a single server the capacity of a data centre.
Zope is developed and maintained by one of the largest open source communities. It was developed in 1998 in the object-oriented programming language Python. Zope stands for ‘Z Object Publishing Environment’ and Zope is helped the programming language Python become popular. It was the first system to start using object publishing methodology for the web.
Magma is a multi-user object database developed especially for Squeak 4.4. It provides good read-transparency to a large-scale shared persistent object model. It has a high-availability and fault tolerance and is developed to support large indexed collections with hard querying.
NDatabase is a .NET Object Database and a transparent persistence layer for .NET. It allows users to store and retrieve native objects with a single line of code. It offers NoSQL and LINQ support and databases are automatic created. It supports different platforms among other Silverlight, Windows Phone and NuGet.
Neoppod is a distributed, redundant and transactional storage system. It was initiated in 2005 and implemented on top of Zope. It is a NoSQL database developed for the cloud.
Sterling is a NoSQL object-oriented database developed especially for Silverlight, Windows Phone 7.0 and .NET. It supports LINQ object queries. The core is light so that the system is flexible and it becomes easy to query the database. Sterling is portable and weighs only 85 kb.
EyeDB is an Object Oriented Database Management System (OODBMS) that is developed by SYSRA. It provides an object model, object definition language, a manipulation language and an object query. It offers programming interfaces for C++ and Java.