Object Database Management System - Essay Example

Object Database Object Database Management System A database is a set of records stored in a computer in an organized way, so that a computerprogram is able to consult it to answer questions. For better recovery and sorting, each record is generally organized as a set of data elements (facts). The objects retrieved in reply to queries become information that can be used to make decisions. The computer program used to control and query a database is known as a database management system (DBMS). An object database is a database within information can be represented in the form of objects. The database management system designed for an object database is referred to variously as a ODBMS or OODBMS. There are two most important factors that lead users to implement object database technology. Firstly, relational databases turn out to be cumbersome to use with composite data. Secondly, data is usually operated by application software written using object-oriented programming languages such as C++, Java, Delphi and C#, and the code required translating between this demonstration of the data and the tuples of a relational database can be dreary to write, and prolonged to execute. This variance between the models used to represent information in the application programs and the database is sometimes referred to as an impedance variance. Now a day Client-Server applications that depends on a database on the server as a data store while servicing requests from multiple clients are quite ordinary. The majority of these applications use a Relational Database Management System (RDBMS) because their data store while using an object oriented programming language for development. The "impedance mismatch" caused as a result of having to map objects to tables and vice versa has long been accepted as an essential performance penalty. Object-oriented databases are designed to work well with object-oriented programming languages such Java, C#, and C++. ODBMS used exactly the same model as object-oriented programming languages. Object database management systems added the notion of persistence to object programming languages. The early commercial products were integrated with various languages: GemStone (Smalltalk), Gbase (Lisp), and Vbase (COP). COP was the C Object Processor, a proprietary language based on C that pre-dated C++. For much of the 1990s, C++ dominated the commercial object database management market. Vendors added Java in the late 1990s and more recently, C#. (Object database - Wikipedia, the free encyclopaedia) Theory We now introduce some basic concept of general system theory. This is essentially a way of understanding a system in terms of those components and characteristics that are common to all systems. We use the term system here in a very specific sense; although one that has much broader application than just computer systems. In everyday speech people may refer to the legal system, a tropical storm system, the system of parliamentary democracy, an eco-system, a system for winning at roulette, a computer system in someone's office, a system for shelving books in a library, a system-build house and many more. Some of these certainly meet our definition of a system and others do not. Probably the only thing that they all have in common is that they have some kind of organization. But in general systems theory, a system is rather more than just anything that shows a degree of organization. Characteristics of a system A system exists in an environment. A system is separated from its environment by some kind of boundary. Systems have inputs and outputs. They receive inputs from their environment and send outputs into their environment. Systems have interfaces. An interface allows communication between two systems. A system may have sub-system. A sub-system is also a system, and may have further sub- systems of its own. Systems that endure have a control mechanism. System control relies on feedback (and sometimes feed-forward). These comprise information about the system's operations or its environment that is passed to the control mechanism. A system has some properties that are not directly depend on the properties of its parts. These are called emergent properties, as they only emerge at the level of the system as a whole. An understanding of the related concepts of boundary and environment is essential to making sense of any system. In fact the first step in understanding a system is to choose the system that you wish to understand and this largely means choosing its boundary. In a pure object database, data is stored as objects which are able to be manipulated only using the methods defined for the class to which the object belongs. Objects are organized into a type hierarchy (sometimes a lattice), and subtypes inherit the characteristics of their super types. Objects can contain references to other objects, and applications can therefore access the data they require using a navigational style of programming. Most object databases also recommend some kind of query language, allowing objects to be found by a more declarative programming approach. It is in the area of object query languages, and the integration of the query and navigational interfaces, that the biggest differences between products are found. Access to data can be faster because joins are often not needed (as in a tabular implementation of a relational database). This is because an object can be retrieved directly without a search, by following pointers. Multimedia applications are facilitated because the class methods associated with the data are responsible for its correct interpretation. Many object databases offer support for versioning. An object can be viewed as the set of all its versions. Also, object versions can be treated as objects in their own right. Some object databases also provide systematic support for triggers and constraints which are the basis of active databases. When you integrate database capabilities with object programming language capabilities, the result is an object database management system (ODBMS). An ODBMS makes database objects appear as programming language objects in one or more object programming languages. An ODBMS extends the language with transparently persistent data, concurrency control, data recovery, associative queries, and other capabilities. An OODBMS is the result of combining object oriented programming principles with database management principles. Object oriented programming concepts such as encapsulation, polymorphism and inheritance are enforced as well as database management concepts such as the ACID properties (Atomicity, Consistency, Isolation and Durability) which lead to system integrity, support for an ad hoc query language and secondary storage management systems which allow for managing very large amounts of data. The Object Oriented Database Manifesto [Atk 89] specifically lists the following features as mandatory for a system to support before it can be called an OODBMS; Complex objects, Object identity, Encapsulation , Types and Classes , Class or Type Hierarchies, Overriding, overloading and late binding, Computational completeness , Extensibility, Persistence , Secondary storage management, Concurrency, Recovery and an Ad Hoc Query Facility. (Simon Bennett, Steve McRobb, Ray Farmer, (2006)) Object Oriented Database Standards The Object Data Management Group (ODMG) was a consortium of object database and object-relational mapping vendors, members of the academic community, and interested parties. Its goal was to create a set of specifications that would allow for portable applications that store objects in database management systems. It published several versions of its specification. The last release was ODMG 3.0. By 2001, most of the major object database and object-relational mapping vendors claimed conformance to the ODMG Java Language Binding. Compliance to the other components of the specification was mixed. In 2001, the ODMG Java Language Binding was submitted to the Java Community Process as a basis for the Java Data Objects specification. The ODMG member companies then decided to concentrate their efforts on the Java Data Objects specification. As a result, the ODMG disbanded in 2001. In February 2006, the Object Management Group (OMG) announced the acquisition of the ODMG 3.0 specification and the formation of the Object Database Technology Working Group (ODBT WG). The ODBT WG plans to work on the next generation of object database specifications. In 2005 Cook, Rai, and Rosenberger proposed to drop all standardization efforts to introduce additional object-oriented query APIs but rather use the OO programming language itself, i.e., Java and .NET, to express queries. As a result, Native Queries emerged. Similarly, Microsoft announced Language integrated query (LINQ) and DLINQ in September 2005, to provide close, language-integrated database query capabilities with its programming languages C# and VB.NET.9 There are several object oriented standards and groups that oversee them. SQL-92 - SQL-92 was developed by the INCITS Technical Committee H2 on Database. SQL is a database sublanguage that is used for accessing relational databases. JDBC - JDBC is a Java API for executing SQL statements. JDBC uses the call-level approach when using the Java programming language. SQLJ - SQLJ was developed by The SQLJ Group, a consortium comprised of database vendors and Sun Microsystems. SQLJ, which stands for "SQL-Java," is a multi-part specification for using SQL with Java SQL:1999 - SQL: 1999 was developed by the INCITS Technical Committee H2 on Database. This committee develops standards for the syntax and semantics of database languages. ADO.NET - ADO.NET provides the database access for Microsoft.NET. ADO.NET is designed to work with all the languages supported in .NET.ADO.NET can be used with virtually any database management system.ADO.NET uses the call-level approach. Java Data Objects (JDO) - The Java Data Objects (JDO) specification is part of the Sun Java Community Process. JDO is a Java application program interface (API) for transparent persistence. It is designed to work well with EJB and J2EE. Object Management Group (OMG) - Develops standards to help make object applications to be portable and communicate between each other (interoperability). They have developed the Component Object Request Broker Architecture (CORBA) standard along with object and OODBMS interfaces. Object Database Management Group (ODMG) - Created to define standard interfaces for object databases. The interfaces should allow the databases and applications that use them be portable and communicate between each other. CASE Data Interchange Format (CDIF) - Defines standards for tools to use so they may be used with various applications such as database servers, application servers, and other tools. Portable Common Tool Environment (PCTE) Standard. PDES/STEP - Exchange format standard for product model data. Also called the object interface format. Object Query Language (OQL) Object Definition Language (ODL) - Extension of OMGs CORBA standard. (DBMS standards) Products The Rational Objectory Process is a Software Engineering Process. It provides a restricted approach to assigning tasks and responsibilities within a growth organization. Its goal is to ensure the production of high-quality software, meeting the needs of its end-users, within a predictable schedule and budget. It captures many of the best practices in modern software development in a form that is tailor able for a wide range of projects and organizations. It focuses on early development and base lining of a robust software architecture, which facilitates parallel development, minimizes rework, increases reusability and maintainability. This architecture is used to plan and manage the development around the use of software components. Objectory supports object-oriented techniques. Several of the models are object-oriented models, based on the concepts of objects, classes and associations between them. These models, like many other technical artefacts, use the Unified Modelling Language (UML) as the common notation. It supports component-based software development. Components are non trivial modules, subsystems that fulfil a clear function, and that can be assembled in a well-defined architecture, either ad hoc, or some component infrastructure such as the Internet, CORBA, and COM, for which an industry of reusable components is emerging. Early products included GemStone (Servio Logic, name changed to GemStone Systems), Gbase (Graphael), and Vbase (Ontologic). The early to mid-1990s saw additional commercial products enter the market. These included ITASCA (Itasca Systems), Matisse (Matisse Software), Objectivity/DB (Objectivity, Inc.), Object Store (Progress Software, acquired from eXcelon which was originally Object Design), ONTOS (Ontos, Inc., name changed from Ontologic), O2[2] (O2 Technology, merged with several companies, acquired by Informix, which was in turn acquired by IBM), POET (now Fast Objects from Versant which acquired Poet Systems), and Versant Object Database (Versant Corporation). Some of these products remain on the market and have been joined by new products. Rational Software, Microsoft, Hewlett-Packard, Oracle Sterling Software, MCI System house, Unisys, ICON Computing IntelliCorp, i-Logix, IBM, ObjecTime, Platinum, Technology, Ptech Taskon, Reich Technologies, Softeam. Another area of variation between products is in the way that the schema of a database is defined. A general characteristic, however, is that the programming language and the database schema use the same type definitions. (The Rational Objectory Process - A UML-based Software Engineering Process) Bibliography DBMS standards http://www.service-architecture.com/database/articles/dbms_standards.html Accessed 13 April, 2006 Object database - Wikipedia, the free encyclopaedia http://en.wikipedia.org/wiki/Object_database Accessed 13 April, 2006 Simon Bennett, Steve McRobb, Ray Farmer, (2006) Object Oriented Systems Analysis and Design using UML, 3/e, McGraw-Hill The Rational Objectory Process - A UML-based Software Engineering Process http://www.iscn.at/select_newspaper/object/rational.html Accessed 13 April, 2006 Read More