Definition Of Relational Database Management System Computer Science Essay

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This section describes definition of relational database management systems, evolution of relational database management systems, explanation of various relational database management systems and its features and advantages of relational database management systems.

Definition of Relational Database Management System

Database is a collection of data. It contains information about one particular enterprise. A database management system (DBMS) consists of a collection of interrelated data and a set of programs to access that data. The primary goal of a DBMS is to provide an environment that is both convenient and efficient to use in retrieving and strong database information. (Kedar, 2009)

A Database Management System (DBMS) is the software that allows one or many persons to use and/or modify data which stored in a database. A major role of the DBMS is to allow the user to deal with the data in abstract terms, rather than as the computer stores the data. (Nwosu et al. 1996)

The relational database management system is a database management system (DBMS) that based on the relational model as introduced E. F. Codd. RDBMS is most popular commercial and open source database management system currently in use is based on the relational database model. A short definition of an RDBMS may be a DBMS in which data is stored in the form of tables and the relationship among the data is also stored in the form of tables.

Evolution of database system technology

Since the 1960s, information technology and database has been developing systematically from primitive file processing systems to sophisticated and powerful database systems. Since the 1970s the research and development in the database systems has progressed from early hierarchical and network database systems to the development of relational database systems, data modeling tools, indexing and accessing methods. A relational database is a collection of different tables. Each table is assigned with a unique name. And each table consists of a set of attributes (rows and columns).

Data Collection and Database Creation

(1960s and earlier)

Primitive file processing

Database Management Systems(1970s-early 1980s)

Hierarchical and network database systems

Relational database systems

Data modeling tools: entity-relational models, etc.

Indexing and accessing methods: B-trees, hashing, etc.

Query languages: SQL, etc.

User interfaces, forms and reports

Query processing and query optimization

Transactions, concurrency control and recovery

On-line transaction processing(OLTP)

Advanced Database Systems (mid-1980s-present)

Advanced data models: extended relational, object-relational, etc.

Advanced applications: spatial, temporal, multimedia, active, stream and sensor, scientific and engineering, knowledge-based

Advanced Data Analysis: Data Warehousing and Data Mining (late 1980s-present)

Data warehouse and OLAP

Data mining and knowledge discovery: generalization, classification, association, clustering, frequent pattern and structured pattern analysis, outlier analysis, trend and deviation analysis, etc.

Advanced data mining applications: stream data mining, bio-data mining, time-series analysis, text mining, Web mining, intrusion detection, etc.

Data mining and society: privacy-preserving data mining

Web-based databases (1990s-present)

XML-based database systems

Integration with information retrieval

Data and information integration

New Generation of Integrated Data and Information Systems (present-future)

The evolution of database system technology adapted from Han(2006)

Advantages by using Relational Database Management System

An RDBMS supports different levels of access. A user may be given permissions to only view the specified tables and fields. Another user may have unrestricted view permissions. Yet another user may have permissions to modify specified tables, or by adding a new table etc.

Data through an RDBMS can be shared without compromising the security of the data.

The integrity constraints can be specified and the RDBMS will ensure that no constraints are violated. These constraints help improve the quality of data.

An RDBMS supports atomicity through its recovery and rollback mechanism. The data is maintained in a consistent state even if some errors and failures occur.

An indirect advantage of an RDBMS is that the organization can enforce standards in naming and documentation. It becomes easy for the management to interpret reports of various departments if they all follow the same standards.(Bansal, 2005)

When not to use Relational Database Management System

It may sound surprising, but there are situations when an RDBMS may not be a viable solution.

If the size of data is small and the relationship among constituents of the data is simple, there is no need to use an RDBMS.

If the usage of data is limited in terms of applications and personnel, an RDBMS is not required.

In a real time application, where response time is the most critical factor, an RDBMS cannot be used.

An RDBMS should not be used for transient data. As the application is non-repetitive in nature, an RDBMS is not required. (Bansal, 2005)

Review of available RDBMS Technologies for educational institutes

There are numbers of relational database management systems (e.g. Access, SQL Server, Oracle, DB2, My SQL etc) are available and any of this can fulfill educational institute's ICT requirement. But at the same time each of these has its own pron and cons. (check Spelling & its meaning) Thus review of available relational database technology for the educational institute is extremely necessary. Following sections describes detail review of relational database technology Microsoft SQL Server and Microsoft Access.

Microsoft SQL Server

Microsoft SQL Server is a relational database management system. It is a product of Microsoft. It is popular database software for database-driven web sites with high traffic. SQL Server is a powerful and fully featured SQL database system.

Evolution of Microsoft SQL Server

The very first version of SQL Server emerged in 1989/1990. It was available for OS/2, and its code base was essentially the same as Sybase SQL Server 4.0. The first edition of SQL Server for Windows NT emerged in 1993 and was a basic port of Sybase SQL Server 4.0 from OS/2 to NT. (Rizzo et al. 2006)

The emergence of SQL Server 6.5 marked the split from Sybase; the database engine was completely rewritten specifically for NT. From that point on, SQL Server has evolved rapidly into a powerful enterprise-level database. SQL Server started life as a small, inexpensive desktop database, with some GUI management tools. (Rizzo et al. 2006)

Microsoft SQL Server 2008

SQL Server 2008 is Microsoft's enterprise-class database server, the upgraded version of Microsoft SQL Server 2000/2005, designed to compete with products such as Oracle and IBM's DB2. SQL Server is rapidly gaining momentum, possessing more than 17 percent of the worldwide database market in 2006. (Chapple, 2008)

SQL Server allows anyone's to store, retrieve, and manipulate data to meet organization's business objectives. The platform provides a number of tools and technologies in managing and manipulating data on own terms. With the help of SQL Server 2008, we can

Import and export data from a variety of file formats.

Link to other databases (both SQL Server and those of other manufacturers).

Manipulate data from within Microsoft Excel and Microsoft Access.

Produce professional-quality dynamic reports based on SQL Server data.

Create automated tasks that trigger when data satisfies specified conditions. (Chapple, 2008)

SQL Server 2008 is available in numerous editions, and the features available in each Edition vary widely. The editions you can install on your workstation or server also vary based on the operating system. The editions of SQL Server range from SQL Express on the lowest end to Enterprise Edition on the highest. The prices of these also vary widely, from free to more than $20,000 per processor. (Knight et al. 2009)

The different editions of SQL Server 2008 are as follows:

Microsoft SQL Server 2008 Compact Edition

Microsoft SQL Server 2008 Express Edition

Microsoft SQL Server 2008 Standard Edition

Microsoft SQL Server 2008 Workgroup Edition

Microsoft SQL Server 2008 Web Edition

Microsoft SQL Server 2008 Developer Edition

Microsoft SQL Server 2008 Enterprise Edition

Microsoft SQL Server 2008 Compact Edition

SQL Compact is a free edition which is intended to be an embedded database for mobile and other compact devices with occasionally connected users. (Knight et al. 2009)

Microsoft SQL Server 2008 Express Edition

SQL Express is the free version of SQL Server meant for installation on laptops or desktops to support distributed applications such as a remote sales force application. People can use this edition to store sales or inventory data for disconnected sales force and replicate updated data to them when they become connected again. SQL Express was called Microsoft Desktop Edition (MSDE) in SQL Server 2000. It is extremely lightweight and does not occupy much hard drive space. Vendors are free to distribute SQL Express, and it can be wrapped into application's installation as just another component. (Knight et al. 2009)

SQL Express is not meant to scale past a few users. Key features missing from SQL Express are SQL Agent and some of the robust management tools. It does ship with a very lightweight tool for managing the database, but scheduling of backups must be done in the Windows Task Scheduler, not SQL Server. (Knight et al. 2009)

Microsoft SQL Server 2008 Standard Edition

The Standard Edition of SQL Server contains high availability clustering features as well as business intelligence. It is intended for small to medium-sized businesses and departmental solutions. (Knight et al. 2009)

Microsoft SQL Server 2008 Workgroup Edition

The Workgroup Edition of SQL Server is the lowest-cost commercial edition of SQL Server. It scales minimally up to two processors and 4GB of RAM (64-bit), but it's adequate for small and medium-sized businesses. There is no limit on the number of users or database size. This edition of SQL Server was initially introduced to compete with lower-end vendors such as MySQL, and should be used for small organizations or departmental applications. It is easily upgraded to the other, more scalable, editions. (Knight et al. 2009)

Microsoft SQL Server 2008 Web Edition

The Web Editions of SQL Server are low cost options intended for web site owners or web hosting companies. These editions include the scalability and manageability features in SQL Server 2008. (Knight et al. 2009)

Microsoft SQL Server 2008 Developer Edition

The Developer Edition of SQL Server is intended for development and testing of applications using SQL Server. It contains all of the features of the Enterprise Edition. This edition is not licensed for production use. (Knight et al. 2009)

Microsoft SQL Server 2008 Enterprise Edition

Enterprise Edition is the best option for SQL Server if anyone needs to use some of the more advanced business intelligence features or if the uptime of database is very important. Although the Standard Edition of SQL Server enables high-availability options, Enterprise Edition far outdoes its sister edition with higher-end clustering as well as more advanced mirroring and log-shipping options. The counter to this, of course, is cost. This edition of SQL Server will cost about $25,000 per processor if anyone chooses that licensing model. (Knight et al. 2009)

Operating Systems supports SQL Server 2008

The edition of SQL Server that you can install varies widely based on the operating system on your server or workstation, as summarized in the following table. The table is representative and does not include each version and service pack for each OS and SQL combination which are supported. (Knight et al. 2009)

Operating System

SQL Express

Workgroup

Web

Standard

Developer

Enterprise

Windows Server 2003 Standard (with SP2+)

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









Windows Server 2003 Enterprise (with SP2+)













Windows Server 2008 Standard

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









Windows Server 2008 Enterprise

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









Windows Server 2008 Data Center

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









Windows 2008 Server Data Center

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









Windows Vista

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







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Windows XP Professional Edition (SP2+)1











Features of MS SQL Server 2008

Restoring Databases

When anyone wishes to recover database data, they must restore the database from backup to an operational state. During a restore, the database is copied from backup, but the restore operation is not marked complete. At this point, any contiguous transactions recorded in the log can be applied to the restored database. This process is known as "roll forward", because it advances the database state to a target recovery point. The recovery point is usually all available data. However, in certain circumstances you may wish to roll the database forward to a specific point in time. Once the restore is marked complete, no subsequent differential or log backups can be rolled forward into the database. (Horninger et al. 2009)

There are multiple possible restore scenarios. The restore scenario you choose depends on your restore requirements and the type of backup you are restoring from. The restore scenarios are dependent on the database recovery model and the SQL Server edition. (Horninger et al. 2009)

Validate data

One of the key goals when building applications is to make sure the data enter into the database meets all business rules. Data validation is a critical part of application to ensure data meets the requirements developed by business analysts. There are a number of different processes that can be used to make sure data validates against business rules. Data validate rules can be enforced within application code in the application layer; or data can be validated by the database engine. Depending on validation, rule requirement will determine where and how it needs to build your application to ensure that the data is properly validated. In this section, researcher is going to discuss how people can use database "check constraints" to validate data within the SQL Server database engine.

What is a check constraint?

A check constraint is a rule that identifies acceptable column values for data in a row within a SQL Server table. Check constraints help enforce domain integrity. Domain integrity defines the valid values for columns within a database table. A check constraint can validate the domain integrity of a single column or a number of columns. User can have multiple check constraint for a single column. If data being inserted or updated violates a check constraint the database engine will not allow the INSERT or UPDATE operation to occur. (Larsen, 2009)

Tools and utilities

A new IDE called SQL Server management Studio for managing SQL Server topologies, databases, and objects; and a collection of new tools for tuning, profiling, and developing SQL Server 2008 solutions. (Hamilton, 2006)

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