Database Management System II What is database management system

Database Management System

A database -management system (DBMS) refers to the collection or the group of programs that enables users  to create and maintain a database. DBMS is general purpose software that organizes data in such a way that it becomes easy to manage, manipulate nd retrieve data from the stored database. Data manipulation in DBMS includes functions such as storing data in the database querying the database to retrieve specific data, updating the database, bring any sort of change in existing database etc. For this purpose different types of database management software such as MS-Access, ORACLE, DBASE, FOXPRO, SYBASE, etc. are used. One of the most remarkable features of Database Management System is to maintain the accuracy of data.

Advantages of Database Management System:

Reduces the data redundancy:

The act of storing the same data multiple times leads to several problems. If data are repeated for multiple times that may led to the duplication of effort and there will be the wastage of storing space. This types of problem can be overcome through the use of database management system. Database management system can easily and automatically control the duplication of data.

Prevents unauthorized access:

Once the database is created, it is shared among the multiple users whoever are in need of that particular information. The entire user may not be equally unauthorized for handling the database. So, the database management system can control the type of access operation-retrieval or update by providing account number protected by password which they can use to access the database.

Helps to store data in organized way:

Database management system enables to user to store data in more organized way in a central database file so that the data can be easily updated, manipulated and accessed back when we are in need of them.

Maintains the consistency of data:

Database management system stores data in organized way in a central location creating a single database file. Any sort of changes that  we bring to the database will have global or mass effect in an entire related data which ensures the overall consistency of database.

Share data locally and globally:

Once the data are stored in database they can be shared among the local user through the computer network and it also can be shared among the other application programs. Not only this, the copy of same data can be exchanged through the Internet globally.

Maintains the accuracy of data:

The data handled , created and manipulated by using database management system are always 100% accurate if the input an process of manipulation is correct. From accurate data we can get accurate information and our decision based on accurate information always produces accurate result.

 

Limitations of Database Management System:

Complexity of the database:

To take full advantages of the Database Management System the database users, administrators, designers and developers should understand the detail functionality of DBMS. The functionality which is supposed to be the fundamental quality of effective and good DBMS makes it more complex.

Size of program becomes large:

The more the functionalities are added to the Database Management System, the more beneficial it becomes. The use of more functionality makes a database file large in size and requires enough memory space to store and run efficiently and smoothly.

Higher impact of a failure:

The centralization of resources increases the dependency on the system. Since, all users and applications depend on the availability of the DBMS. So, any sort of failure in a central database may cause overall system halt.

Additional Hardware costs:

For the smooth functioning of the Database Management System requires computer with high processing speed and large storage capacity. So, to buy this type of computer results further expenditure.

 

Types of Database Management System

Database management systems also known as database model are crucial and important links in the creation as well as management of data. They are needed for effective running and management of data which help to transfer the data through the entire systems. There are different types of Database Management Systems. Some of them are discussed below:

Flat File Based Database Management Systems (FFBDBMS)

The Database Management system that stores data in a single table called is called Flat File Based Database Management System. Flat file database is generally in plain-text form in which each line holds only one record. The records or data in this database management system are separated by comma or tabs.

Hierarchical Database Management Systems (HDBMS)

The Hierarchical Database Management Systems is the first database model created by IBM in 1960s. In HDBMS data and information are organized into tree like structure. The data stored like records are connected to each other through links. In this model, record is the composed of related fields. The fields determines the types of records it contains.

Network Database Management Systems (NDBMS)

Network Database Management Systems uses the tree structure in the Network model, which can have many to many relations such as many children to parent or many parent to child relation. In this model, relationships, are in a net-like form where a single element can point to multiple data elements and can  be itself pointed to by multiple data elements.

Object-oriented Database Management Systems (OODBMS)

An object-oriented database management system supports the modeling and creation of data as objects. This includes some kind of support for classes of objects and the inheritance of class properties and methods by subclasses and their objects. In Object-oriented Database Management Systems data and information are not presented in a tabular form rather they are presented in the form of object.

Relational Database Management Systems

RDBMS is one of the most popular Database Management System used today, because it is easy to use and user friendly. The relational database management system stores the data in multiple tables in the form of rows and columns. In RDBMS, we can create number of tables to store varieties of information which can be interlinked through relationship to manage data correctly. The interlinked table can communicate and shared information. In RDBMS data can be accessed from the multiple tables and can be updated from a single place. Data in RDBMS are stored in fixed predefined structures are usually manipulated using Structured Query Language (SQL). Relational database management systems include MS-Access, Oracle, My SQL etc.

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