Relational Database Management Systems
Object Oriented Databases
The database world is in a constant change! New techniques for concurrency control, cloud platforms, object databases, and service platforms are all being changed and talked about in the industrial and academic world. OODB has been around since the seventies when object oriented programming was first being developed. That being said; companies have only started using object oriented databases in the last ten to fifteen years.
In the early 1980’s a Microelectronics and Computer Technology Corporation employee begins ORION. ORION is able to handle schema evolution and complex object looking. During the late 1980’s the first wave of commercial OODMS hits. In this time period we get the beginning of Graphael, which later becomes Matisse. Designed to benefit all perspectives of object oriented databases, Matisse combines native support for SQL, Object and XML all in a single database. Next we get the GemStone Systems, the earliest OODB that supports object identity, inheritance and encapsulation. On into the late 1980’s France starts the development of O2. It is C++ compatible and supports multiple inheritances. Later on Vbase was produced, which use the language COP. COP is changed into a C++ based system that supports encapsulation, ability to construct complex objects, and inheritance. (“Short History”, 2005)
Once we get into the 1990’s the first standard is released, ODMG 1.0. During this time frame a common query language is the main goal. Object query language is very influence by this period, these efforts lead to SQL: 1999. Once 2000 hits we get the final ODMG 3.0 standard. “ODMG submits the ODMG Java Binding to the Java Community Process as a basis for the Java Data Objects (JDO) Specification. Afterwards, the ODMG disbands.” (“History”, 2005) DB4O is released in 2004 as a free, open source ODBMS. It is the first to take on “Native Queries” and relied entirely on JAVA and C#.
Object oriented databases, or Object Database Management Systems (ODBMS), store objects rather integers, strings or real numbers. Languages used in object oriented databases can be Smalltalk, C++, Java, and others. Objects basically consist of the attributes, data that defines the characteristics of an object, and methods, define the behavior of an object. Another characteristic of the database consist of classes. These are used to define the data and methods the object will contain. The class itself does not contain data or methods, but defines the data and methods contained in the object. The class is used to create the object.
When you have complex data and/or complex data relationships you should use an object database. Object databases work the best with: Multimedia Applications, Object projects that can gradually change over a period of time, and Commerce. There are many advantages and disadvantages for using an object database over a relational database. A few advantages are object databases require less code, you have a better concurrency control, easier navigation, and objects don’t require assembly and disassembly. Disadvantages compared to a relational database are relational tables are simpler, more tables exist in a relational database, standards are more constant, and support is more confident and less change is required. (“Object Oriented Databases”, 2000)
Standards for an object database are the following: 1. “OD Management Group 2. Object Database Standard ODM6.2.0 3. Object Query Language 4. OQL support of SQL92” (“Object Oriented Databases”, 2000)
Object oriented databases should be consider and implemented in many different situations. Embedded database management applications is an example of one, because packing Java/ .NET objects is always the least invasive way to execute a persistence solution.
Another being in complex data relationships where there is a complex cross referencing between objects that can be difficult and inclined to mistakes in a relational database system. Also when your data is being accessed by navigation and not by query, an object oriented database is the way to go; since data is stored in a networked arrangement, and data access if mainly through navigation within the object structure. (“When to Use an ODBMS”, 2005)
Now in days businesses are starting to incorporate OODBMSs. An OODB is just another tool that can be used when appropriate to maximize profit. Some database engines commonly used in businesses today are: Ontos, ITASCA, Versant, ObjectStore, Objectivity, and Objectory/DB. (Chandler, 2002) Web applications have a great advantage with this because of the speed and flexibility of the object oriented style. With the growth in the use of XML as the support of web applications, object oriented databases will be a key to bring online databases and applications that using OODBMSs together.
References:
Short History. ODBMS.ORG. (2005). Retrieved from http://www.odbms.org/Introduction/history.aspx.
Object Oriented Databases. The Computer Technology Documentation Project (2000). Retrieved from http://www.comptechdoc.org/independent/database/basicdb/dataobject.html
When to Use an ODBMS.ODBMS.ORG.(2005). http://www.odbms.org/Introduction/whenODBMS.aspx
Chandler, Jane. Object Oriented Databases.( October 2002). Retrieved from http:// dis.port.ac.uk/~chandler/OOLectures/database/database.htm 