What is a DBMS (Database Management System)?

Database Management System (DBMS):

A DBMS is a set of computer programs that controls the creation, maintenance and the use of the database with computer as a platform and its end users. DBMS is a system software package that helps the use of integrated collection of data records and files known as databases. It allows different user application programs to easily access the same database.

DBMS may use variety of database models such as network model, hierarchical or relational model. In large systems, a DBMS allow users and other software to store and retrieve data in structured way.  User can ask simple questions in a query language instead of having to write computer programs to extract required information.

Many DBMS packages provide 4th Generation Programming Language (4GL) and other application development features.  It helps to specify the logical organisation for a database, use of information within a database as well as facilities for controlling data access, data integrity enforcement, managing   concurrency control and restoring of database etc.

  

DBMS or Database:

DBMS is a collection of interrelated data and set of programs to access those data. The collection of data is referred as the database which contains information relevant to an enterprise or an organization.

 

The primary goal of a DBMS is to provide a way to store and retrieve database information that is both convenient and efficient. These systems are designed to manage vast information. The management of data involves defining structures for storage of information and providing a mechanism for the manipulation of information.

 

Further, the database system must ensure the safety of the information stored, even if a system crashes or attempts of unauthorized access are made to it. If data are to be shared among several users, the system must avoid possible inconsistent results.

 

 Applications of DBMS:

1. Banking:  for storing customer information, accounts, loans and banking transactions.

2. Airlines:  for reservations and schedule information. 

3. Universities:  for student information, course registration and grades.

4. Credit card transactions:  for purchases on credit cards and generation of monthly statements.

5. Telecommunication:  for keeping records of calls, generating monthly bills, maintaining balance, storing information about the communication networks, etc.

6. Finance: to store information about holdings, sales and purchase of financial instruments such as stocks and bonds.

7. Manufacturing:  to manage supply chain and for tracking production of items in factories, inventories of items in warehouses and orders for items.

8. Sales:  for customer, product and purchase information.

9. HR:  to store information about employees, salaries, payroll, taxes and benefits, pay cheque generation, etc.

  

 Advantages of DBMS:

 

 A DBMS generally should provide the following advantages over a traditional file system:

1.    Data and Program Independence:  it is a key advantage of a database.  Both the database and the user program can be altered independently of each other.   This helps in saving time and money which would be required to retain consistency.

2.   Data Sharing and Non-redundant Data: an ideal situation is to enable applications to share an integrated database containing all the data needed by the applications. This eliminates the need to store redundant (duplicate) data as much as possible.

3.    Data Inconsistency:  a database which is in an inconsistent state may supply either incorrect or a conflicting information.  The inconsistency can be avoided by using propagation updates.

4.    Integrity:  with many different users sharing various portions of the database it is impossible for a user to be responsible for the consistency of the values in the database and to maintain the relationships among various data items in the database.

5.    Centralized Control:  DBA has central control over the database and he can ensure that standards are followed in representing the data.

6.    Security:  DBA can ensure that access to the database is through proper channels and can define the access rights of any user to any data item, thereby preventing corruption of existing data either accidently or maliciously.

7.    Performance and Efficiency: as size of the database increases, good performance and efficiency become a major requirement. The DBA can design database system to provide an overall service that is best for an organization knowing the overall requirements of the organisation.

  

 Disadvantages of DBMS:

1. Developing or purchasing cost of the software is very high.

2. It requires more workspace for execution and storage.

3. Complex backup and recovery operations.

4. Backup facility must be provided because in case the system crashes data must be recovered.