FOREIGN KEY. The FOREIGN KEY constraint is a key used to link two tables together. A FOREIGN KEY is a field (or collection of fields) in one table that refers to the PRIMARY KEY in another table.

In SQL, the FOREIGN KEY constraint is used to create a relationship between two tables. A foreign key is defined using the FOREIGN KEY and REFERENCES keywords. Example

Jan 15, 2025 · The syntax to create a foreign key in CREATE TABLE statement is: CONSTRAINT fk_constraint_name FOREIGN KEY (column1, column2, …) REFERENCES parent_table (column1, column2, …) ); The syntax to add a foreign key with ALTER TABLE statement is: ADD CONSTRAINT fk_constraint_name FOREIGN KEY (column1, column2, …)

Feb 4, 2025 · This article describes how to create foreign key relationships in SQL Server by using SQL Server Management Studio or Transact-SQL. You create a relationship between two tables when you want to associate rows of one table with rows of another.

Nov 27, 2020 · A SQL foreign key is a field in one table that points to a field in another table (often, the second table's primary key). This links the two database tables, keeping the database consistent and connected.

This tutorial helps you understand SQL foreign key and show you how to define a foreign key using the FOREIGN KEY constraints.

Apr 5, 2019 · In this article let us review different ways to create a SQL foreign key, rules on updates and deletes, enabling foreign key constraints, disabling foreign key constraints and not for replication in foreign keys. What is a foreign key? A Foreign key is constraint that enforces referential integrity in SQL server database.

Summary: In this tutorial, you will learn how to use the SQL Server foreign key constraint to enforce a link between the data in two tables. Consider the following vendor_groups and vendors tables: group_id INT IDENTITY PRIMARY KEY, group_name VARCHAR (100) NOT NULL . CREATE TABLE procurement.vendors ( vendor_id INT IDENTITY PRIMARY KEY,

Jan 7, 2020 · In this one, we’ll check what is the foreign key (FK) and how it’s related to the primary key. This is the final step, after creating tables, inserting data, and defining primary keys, to cover all basics related to the database theory.

Feb 13, 2020 · A foreign key is a column or set of columns that allow us to establish a referential link between the data in two tables. This referential link helps to match the foreign key column data with the data of the referenced table data. The referenced table is called the parent table and the table that involves a foreign key is called the child table.