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 …

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

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 …

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 …

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.

A foreign key is a field (or collection of fields) in one table that uniquely identifies a row of another table. The table containing the foreign key is known as the child table, and the table containing the …

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 …

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 stays consistent …