Posts

Showing posts from August, 2024

Integrity Constraints

Integrity constraints in a Database Management System (DBMS) are rules that ensure the accuracy and consistency of data within the database. These constraints enforce certain conditions on the data, preventing invalid or inconsistent data from being entered or manipulated. Integrity constraints are crucial for maintaining the quality and reliability of the database --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- Types of Integrity Constraints Domain Integrity Definition: Ensures that all values i

Types of Schema in DBMS and their Characteristics

Types of Schema in DBMS and their Characteristics 1. Physical Schema Description: This schema describes how the data is physically stored in the database. It deals with the storage and access methods, file organization, indexing, and data compression. Characteristics: Defines the storage structure and access methods. Deals with physical data storage, including tablespaces, indexes, partitions, etc. Managed by the DBA (Database Administrator) and usually hidden from end-users. Focuses on optimization for performance, such as disk space usage, data retrieval speed, and backup mechanisms. 2. Logical Schema Description: This schema defines the logical structure of the database. It represents the overall design and structure of the database, including tables, views, constraints, and relationships. Characteristics: Represents the logical view of the entire database. Defines tables, columns, data types, relationships, primary and foreign keys. Independent of the physical storage considera