Purpose of Database Systems | Learn DBMS for GATE & Competitive Exams
Purpose of Database Systems
Introduction
Database systems evolved to address the limitations of early file-processing systems used for managing commercial data. Before the advent of Database Management Systems (DBMS), organizations relied on conventional operating systems to store and process information in files. These systems, while functional, introduced several challenges, leading to the development of more advanced and efficient DBMS solutions.
Challenges with File-Processing Systems
1. Data Redundancy and Inconsistency
File-processing systems often stored the same data in multiple locations. For example, a university might maintain separate files for students in different departments, such as music and mathematics. If a student updates their address, one file may reflect the change, while others remain outdated, leading to inconsistencies.
Example: A student’s phone number stored in multiple files may result in conflicting information when updates are not synchronized.
2. Difficulty in Accessing Data
File-processing systems lacked flexibility for data retrieval. If a university clerk needed a list of students from a specific postal code, and no application existed to generate it, the only options were manual extraction or programming a new application—both inefficient solutions.
3. Data Isolation
Data scattered across multiple files in different formats made it difficult to create new applications or retrieve data efficiently. For example, combining student data from various departments required significant effort.
4. Integrity Problems
Maintaining data integrity was challenging in file-processing systems. For instance, ensuring a department’s account balance does not drop below zero required adding custom code to every application interacting with the data. Updating such constraints was labor-intensive and prone to errors.
5. Atomicity Problems
Atomicity ensures that database transactions occur entirely or not at all. In file-processing systems, failures during a transaction (e.g., transferring funds between accounts) could leave data in an inconsistent state.
Example: If $500 is deducted from one account but not credited to another due to a system failure, the database state becomes inconsistent.
6. Concurrent-Access Anomalies
File-processing systems struggled with simultaneous data updates. For instance, two clerks withdrawing money from the same account at the same time might overwrite each other’s updates, leading to incorrect balances.
Example: If the account balance is $10,000 and two withdrawals of $500 and $100 occur concurrently, the final balance might incorrectly show $9,500 or $9,900 instead of $9,400.
7. Security Problems
File-processing systems lacked robust security mechanisms. Restricting access to specific data, such as financial information for payroll staff, required significant effort, often resulting in vulnerabilities.
How Database Systems Address These Challenges
1. Reduced Data Redundancy
DBMS uses normalization techniques to organize data efficiently, eliminating unnecessary duplication and reducing storage costs.
2. Simplified Data Access
With structured query languages (e.g., SQL), retrieving data in DBMS is straightforward and efficient, allowing users to perform complex queries with ease.
3. Enhanced Data Integrity
DBMS enforces integrity constraints, such as primary keys and foreign keys, to maintain data consistency automatically.
4. Support for Atomic Transactions
DBMS ensures atomicity, consistency, isolation, and durability (ACID properties), safeguarding data integrity even during failures.
5. Concurrent Access Control
With concurrency control mechanisms, DBMS prevents anomalies arising from simultaneous data updates by multiple users.
6. Robust Security
DBMS allows role-based access control, ensuring that users can only access data relevant to their roles.
Conclusion
Database systems have revolutionized data management by addressing the limitations of traditional file-processing systems. With features like data integrity, efficient access, atomic transactions, and robust security, DBMS is an essential tool for modern organizations and a crucial topic for competitive exams like GATE, UGC NET, and ISRO.
