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 parent table, the …

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 Orders table is a …

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

Oct 29, 2025 · A foreign key in SQL is a column (or a set of columns) that links one table to the primary key of another table. It creates a relationship between two tables and helps maintain data consistency.

In SQL, a Foreign Key is a column in one table that refers to the Primary Key in another table, creating a connection between the two tables. A foreign key ensures referential integrity by making sure that …

Nov 18, 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 …

Jul 31, 2025 · A foreign key is a validation rule in the database that links one table to another by matching values. It helps keep your data linked correctly and stops you from adding values that don’t …

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 …

A FOREIGN KEY is a field (or collection of fields) in one table that refers to the PRIMARY KEY in another table. The table containing the foreign key is called the child table, and the table containing …