SQL Foreign key

Foreign Key vs Primary Key - What is the Difference? - Essential SQL

Learn SQL: Foreign Key

Commonly used SQL Server Constraints: FOREIGN KEY, CHECK and DEFAULT

Script Constraints, Primary and Foreign Keys for SQL Server Database

How to create a SQL Server foreign key

Q1.Answer the following:(10)a. Is it mandatory for a foreign key to be a primary key in another table?b. Can foreign keys be null values in child relation?c. After enforcing foreign key constraint using on delete cascade rule, can you delete therecord in the child relation whose foreign key is not null before deleting the record in theparent relation?d. Can foreign keys have the duplicate values?e. Can there exist more than one foreign key in relation?Q2. Create fully normalized ERDs with primar

What is a foreign key in SQL Server

Adding foreign key to a table using Sequelize