Introduction to DBMS

Study Notes

A Database Management System (DBMS) is a collection of related data and programs used to access and utilize that information.
The primary goal of a DBMS is to ensure efficient and convenient storage and retrieval of data.

DBMS are designed to manage large sets of information.
Data management includes defining storage structures, providing manipulation mechanisms, and ensuring data safety.

Redundant and inconsistent data: Multiple files with different structures and formats, leading to data duplication.
Difficulty in information access: Retrieval and manipulation of data across different files becomes challenging.
Data isolation: The scattered nature of data in various formats hinders the creation of new applications.
Integrity issues: Maintaining data consistency through constraints can be challenging.
Atomicity problems: Ensuring data restoration to a consistent state after system failure is crucial.
Concurrent-access anomalies: Managing simultaneous access to data by multiple users leads to inconsistencies.
Security problems: Controlling access to sensitive information based on user privileges is a significant concern.

DBMS provides users with an abstract view of data, hiding storage and maintenance details.
This abstraction enables efficient data retrieval by employing complex data structures.

Physical level details how data is stored in the system and focuses on low-level data structures.
Logical level describes the data types and relationships within the database.
View level provides a tailored portion of the entire database, offering different perspectives on the data.

Application programs are said to be physically data independent when they are not affected by changes to the physical schema, allowing for schema modifications without rewriting applications.