Database Integrity Constraints and Relational Algebra Operations
What are Integrity Constraints?
Integrity constraints are predefined rules used to maintain data quality. They ensure that data insertion, updates, and deletions are performed without affecting data integrity. These constraints act as guidelines, ensuring data accuracy and consistency, thus protecting databases.
Types of Integrity Constraints:
- Domain Constraints
- Not-Null Constraints
- Entity Integrity Constraints
- Key Constraints
- Primary Key Constraints
- Referential Integrity Constraints
Importance of Referential
Read MoreDatabase Management Systems: Keys, Entities, and Normalization
Types of Keys in SQL
In SQL, a key is used to identify a record in a database table. There are several types of keys:
- Primary Key: Uniquely identifies each record in a table. Each table can have only one primary key.
- Foreign Key: A column or a set of columns in one table that refers to the primary key of another table. It is used to establish relationships between tables.
- Candidate Key: A set of attributes that could uniquely identify a record in a table. A table can have multiple candidate keys.
- Alternate
Relational Database Concepts and SQL Fundamentals
Normalization
Normalization is a database design technique used to organize the structure of relational databases. The goal is to reduce data redundancy and improve data integrity by dividing large tables into smaller ones and defining relationships between them. The process involves several normal forms (1NF, 2NF, 3NF, BCNF, etc.), each with its own set of rules:
- 1NF (First Normal Form): Ensures that each column contains atomic values (no repeating groups).
- 2NF (Second Normal Form): Ensures that the