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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. The following SQL creates a FOREIGN KEY on the "PersonID" column when the "Orders" table is created:
To create a new table containing a foreign key column that references another table, use the keyword FOREIGN KEY REFERENCES at the end of the definition of that column. Follow that with the name of the referenced table and the name of the referenced column in parentheses.
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.
To Create a foreign key on any table . ALTER TABLE [SCHEMA].[TABLENAME] ADD FOREIGN KEY (COLUMNNAME) REFERENCES [TABLENAME](COLUMNNAME) EXAMPLE ALTER TABLE [dbo].[UserMaster] ADD FOREIGN KEY (City_Id) REFERENCES [dbo].[CityMaster](City_Id)
22 lip 2024 · 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.
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
This tutorial helps you understand SQL foreign key and show you how to define a foreign key using the FOREIGN KEY constraints.
