Introduction to DBMS
A Database is an organized collection of related data. The data is typically organized to model relevant aspects of reality. Database systems constitute the most important component of any computer-based information system.
A Database Management System (DBMS) is a collection of programs that enables users to create, maintain, and manipulate databases.
Traditional File Systems vs. DBMS
Before the advent of database management systems, information was stored via file processing systems supported by a conventional operating system. However, the file system approach has several limitations:
| Limitation in File Systems | How DBMS Solves it |
|---|---|
| Data Redundancy | Centralized architecture removes duplicate files and promotes data sharing. |
| Data Isolation | Data is no longer scattered in various files with different formats. |
| Integrity Problems | Checks are automatically enforced via database constraints. |
| Concurrent Access Anomalies | Transaction and locking mechanisms allow safe simultaneous access. |
Visual Comparison
Functions and Facilities of a DBMS
- Authorization & Security Services: Ensure only authorized users access the data.
- Integrity Services: Ensure that both the data and changes follow defined constraints.
- Concurrency Control: Manages simultaneous requests without compromising data consistency.
- Recovery Control: Restores the database to a consistent state following an error or a crash.
- Transaction Support: Guarantees ACID properties (Atomicity, Consistency, Isolation, Durability).