Functions of Database Management System (DBMS)
Here we discus the different Functions of Database Management System(DBMS). DBMS performs several important functions that guarantee the integrity and consistency of the data in the database. The most important functions of Database Management System are
Data Dictionary Management,
Data Storage Management,
Data Transformation and Presentation,
Security Management,
Multi user Access Control,
Backup and Recovery Management,
Data Integrity Management,
Database Access Languages andApplication Programming Interfaces and
Database Communication interfaces.
1. Data Dictionary Management
Data Dictionary Management is the one of the most important function in database management system.
DBMS stores definitions of the data elements and their relationships (metadata) in a data dictionary.
So, all programs that access the data in the database work through the DBMS.
The DBMS uses the data dictionary to look up the required data component structures and relationships which relieves you from coding such complex relationships in each program.
Additionally, any changes made in a database structure are automatically recorded in the data dictionary, thereby freeing you from having to modify all of the programs that access the changed structure.
In other words, the DBMS system provides data abstraction, and it removes structural and data dependence from the system.
2. Data Storage Management
The DBMS creates and manages the complex structures required for data storage, thus relieving you from the difficult task of defining and programming the physical data characteristics.
A modern DBMS system provides storage not only for the data, but also for related data entry forms or screen definitions, report definitions, data validation rules, procedural code, structures to handle video and picture formats, and so on.
Data storage management is also important for database performance tuning. Performance tuning relates to the activities that make the database perform more efficiently in terms of storage and access speed. So, the data storage management is another important function of Database Management System.
3. Data transformation and presentation
The DBMS transforms entered data in to required data structures. The DBMS relieves you of the chore of making a distinction between the logical data format and the physical data format. That is, the DBMS formats the physically retrieved data to make it conform to the user’s logical expectations.
For example, imagine an enterprise database used by a multinational company. An end user in England would expect to enter data such as July 11, 2009, as “11/07/2009.” In contrast, the same date would be entered in the United States as “07/11/2009.” Regardless of the data presentation format, the DBMS system must manage the date in the proper format for each country.
4. Security Management
Security Management is another important function of DBMS. The DBMS creates a security system that enforces user security and data privacy. Security rules determine which users can access the database, which data items each user can access, and which data operations (read, add, delete, or modify) the user can perform. This is especially important in multiuser database systems.
5. Multi User Access Control
To provide data integrity and data consistency, the DBMS uses sophisticated algorithms to ensure that multiple users can access the database concurrently without compromising the integrity of the database.
6. Backup and Recovery Management
The DBMS provides backup and data recovery to ensure data safety and integrity.
Current DBMS systems provide special utilities that allow the DBA to perform routine and special backup and restore procedures. Recovery management deals with the recovery of the database after a failure, such as a bad sector in the disk or a power failure. Such capability is critical to preserving the database’s integrity.
7. Data Integrity Management
Data integrity management is another important funcion of DBMS.
The DBMS promotes and enforces integrity rules, thus minimizing data redundancy and maximizing data consistency.
The data relationships stored in the data dictionary are used to enforce data integrity. Ensuring data integrity is especially important in transaction-oriented database systems.
8. Database Access Languages and Application Programming Interfaces
The DBMS provides data access through a query language. A query language is a non procedural language—one that lets the user specify what must be done without having to specify how it is to be done.
Structured Query Language (SQL) is the defacto query language and data access standard supported by the majority of DBMS vendors.
9. Database Communication Interfaces
Current-generation DBMS's accept end-user requests via multiple, different network environments. For example, the DBMS might provide access to the database via the Internet through the use of Web browsers such as Mozilla Firefox or Microsoft Internet Explorer. In this environment, communications can be accomplished in several ways:
- End users can generate answers to queries by filling in screen forms through their preferred Web browser.
- The DBMS can automatically publish predefined reports on a Website.
- The DBMS can connect to third-party systems to distribute information via e-mail or other productivity applications.