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To allow naming of a FOREIGN KEY constraint, and for defining a FOREIGN KEY constraint on multiple columns, use the following SQL syntax: MySQL / SQL Server / Oracle / MS Access: ALTER TABLE Orders. ADD CONSTRAINT FK_PersonOrder.
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.
To allow naming of a FOREIGN KEY constraint, and for defining a FOREIGN KEY constraint on multiple columns, use the following SQL syntax: MySQL / SQL Server / Oracle / MS Access: ALTER TABLE Orders
The general syntax for creating a FOREIGN KEY constraint is as follows: CONSTRAINT fk_constraint_name FOREIGN KEY (column_1, column2,...) REFERENCES parent_table_name (column1,column2,..) Code language:SQL (Structured Query Language)(sql) Let’s examine this syntax in detail.
You first need to check if the primary-key exists for the column you want to set your foreign key to reference to. In this example, a foreign key on table T_ZO_SYS_Language_Forms is created, referencing dbo.T_SYS_Language_Forms.LANG_UID -- First, chech if the table exists...
Syntax: Foreign Key. CONSTRAINT <foreignkey_name> FOREIGN KEY (<column_name>) REFERENCES <reference_tablename> (<column_name>) [ON DELETE CASCADE] [ON UPDATE CASCADE] In the above syntax, <foreignkey_name> is the name of a foreign key that should be in the FK_TableName_ReferenceTableName format to recognize it easily.
In this tip we look at how to create a SQL Server foreign key using both T-SQL and the SSMS GUI.
