A foreign key is a database constraint that creates a relationship between two tables by linking a column or a set of columns in one table to the primary key of another table. This ensures referential integrity, meaning that the foreign key column must contain values that exist in the referenced primary key column or be null.

Foreign Key

foreign key

Database constraints are rules enforced on data in a database to ensure its accuracy, integrity, and reliability. They prevent invalid data entry and maintain data consistency across the database system by defining specific conditions that data must meet before being stored.

database constraint

relationship between two tables

linking a column

set of columns

A primary key is a unique identifier for a record in a database table, ensuring that each entry is distinct and easily retrievable. It is essential for maintaining data integrity and establishing relationships between tables in a relational database management system.

primary key

Referential integrity is a property of relational databases that ensures relationships between tables remain consistent, where foreign keys correctly reference primary keys. It prevents the creation of orphaned records and maintains data accuracy by enforcing constraints during data manipulation operations.

referential integrity

foreign key column

values that exist

referenced primary key column

Foreign Keys: Establishing Relationships in Databases

Introduction to SQL Table Fundamentals

Creating Tables in SQL

Comprehensive Guide to SQL Table Creation for Aspiring App Developers

Creating Tables in SQL for App Development

Fundamental Skills in SQL: Creating Tables for App Development

Introduction to SQL Tables and Their Structure

Understanding SQL Table Structure and Rules in Mastering SQL Table Creation

Introduction to SQL Joins

Understanding SQL Joins with Customer and Order Tables

Understanding Customer Responses in SQL JOIN Operations

Left Join

Introduction to Relational Databases and SQL Syntax

Database Design

Data Modeling and Database Design

Defining Primary and Foreign Keys in SQL Tables

Database Normalization

Database Architecture

Understanding Database Fundamentals and Architecture

Introduction to Relational Databases

Introduction to SQL and Database Fundamentals

Introduction to SQL Syntax and Queries

Introduction to Database Fundamentals

Entity-Relationship Model

Mastering Eloquent Relationships and Query Optimization

SQL Concepts

Introduction to MySQL

Relevant Degrees

Log in to see lessons