A database management system (DBMS) or database system in short, is a software that can be used to create and manage databases. DBMS lets users create a database, store, manage, update/modify and retrieve data from that database by users or application programs.
Some examples of open source and commercial DBMS include MySQL, Oracle, PostgreSQL, SQL Server, Microsoft Access, MongoDB.
A database system hides certain details about how data are actually stored and maintained. Thus, it provides users with an abstract view of the data.
The DBMS serves as an interface between the database and end users or application programs.
Retrieving data from a database through special types of commands is called querying the database. In addition, users can modify the structure of the database itself through a DBMS.
Need for Database Management System
There are many reasons why DBMS are needed, such as:
- Data independence : DBMS allows users to access data without knowing the physical details of how and where the data is stored. This makes it easier to change the structure or location of the data without affecting the applications that use it.
- Data integrity : DBMS ensures that the data is accurate, consistent, and valid. It enforces rules and constraints on the data, such as primary keys, foreign keys, domain constraints, etc. It also prevents unauthorized access or modification of the data.
- Data security : DBMS protects the data from unauthorized access or disclosure. It provides mechanisms for authentication, authorization, encryption, auditing, etc. It also allows users to specify different levels of access rights for different users or groups.
- Data consistency : DBMS ensures that the data is consistent across different applications and users. It maintains a single copy of the data and avoids duplication or redundancy. It also supports transactions, which are atomic, consistent, isolated, and durable (ACID) operations on the data.
- Data efficiency : DBMS improves the performance and efficiency of accessing and manipulating data. It provides techniques for indexing, caching, buffering, compression, etc. It also optimizes the queries and executes them faster.
- Data sharing : DBMS allows multiple users and applications to access and share the same data concurrently. It supports concurrency control, which prevents conflicts or errors due to simultaneous access or modification of the data. It also supports distributed databases, which allow data to be stored and accessed across multiple locations.