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.

Jul 23, 2025 · A FOREIGN KEY constraint is a fundamental concept in relational databases, ensuring data integrity by enforcing relationships between tables. By linking a child table to a …

The FOREIGN KEY constraint in SQL establishes a relationship between two tables by linking columns in one table to those in another. For example, Here, the customer_id field in the …

In SQL, a foreign key is a column or a set of columns in a table that references the primary key of another table. A table with a foreign key is called a child or foreign key, or referencing table.

Aug 7, 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 …

Using foreign key SQL constraints ensures data integrity, enforces business rules, and enables consistent interactions across multiple tables. This guide explains what a foreign key in SQL …

Oct 22, 2024 · In this tutorial, we’ll illustrate how to add a foreign key constraint to an existing SQL table. In our examples, we’ll use Baeldung’s simple University database.

May 25, 2025 · The foreign key constraint is your key to building reliable relationships in SQL databases. By linking tables and enforcing referential integrity, foreign keys ensure your data …

In this article, I’ll explain how FOREIGN KEY works in SQL and provide the best FOREIGN KEY examples to help you build robust database schemas. What Is a FOREIGN KEY in SQL? A …

Oct 3, 2025 · A foreign key is applied to a column (or attribute) of one table which references the primary key of a column in another table. It act as a cross-reference between two tables.