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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
Learn how to use the FOREIGN KEY constraint to link two tables together in SQL. See examples of creating, naming, and dropping FOREIGN KEY constraints in different databases.
The FOREIGN KEY constraint is used to prevent actions that would destroy links between tables. A FOREIGN KEY is a field (or collection of fields) in one table, that refers to the PRIMARY KEY in another table.
This tutorial helps you understand SQL foreign key and show you how to define a foreign key using the FOREIGN KEY constraints.
15 cze 2024 · A foreign key constraint in SQL is a rule that links two tables by requiring values in one table's column to match values in another table's column. It ensures data relationships are maintained and prevents orphaned records.
27 lis 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.
5 kwi 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.
