How can I update the foreign keys to make them ON CASCADE UPDATE ? Thus NO ACTION is taken after updating my primary keys columns. , I see that update_referential_action is set to 0. When I run followinq query select * from sys.foreign_keys where referenced_object_id=OBJECT_ID('myTable') In this foreign key example, we've created a foreign key on the inventory table called fk_inv_product_id that references the products table based on the product_id field.Is it possible to update a primary key column value with cascading the update among all the foreign keys referencing it ? Let's look at an example of how to create a foreign key with cascade delete in SQL Server (Transact-SQL) using the ALTER TABLE statement. ON DELETE CASCADE It specifies that the child data is deleted when the parent data is deleted. The foreign key will enforce a link between this data and the child_col1, child_col2. parent_col3 The columns that make up the primary key in the parent_table. parent_table The name of the parent table whose primary key will be used in the child_table. child_col_n The columns in child_table that will reference a primary key in the parent_table. fk_name The name of the foreign key constraint that you wish to create. ON DELETE CASCADE child_table The name of the child table that you wish to modify. The syntax for creating a foreign key with cascade delete using an ALTER TABLE statement in SQL Server (Transact-SQL) is: ALTER TABLE child_table So in this example, if a product_id value is deleted from the products table, the corresponding records in the inventory table that use this product_id will also be deleted.Ĭreate a foreign key with cascade delete - Using ALTER TABLE statement Syntax The foreign key establishes a relationship between the product_id column in the inventory table and the product_id column in the products table.įor this foreign key, we have specified the ON DELETE CASCADE clause which tells SQL Server to delete the corresponding records in the child table when the data in the parent table is deleted. We have used the CREATE TABLE statement to create a foreign key on the inventory table called fk_inv_product_id. Next, we've created a second table called inventory that will be the child table in this foreign key with cascade delete example. The products table has a primary key that consists of the product_id field. In this foreign key example, we've created our parent table as the products table. Let's look at an example of how to create a foreign key with cascade delete in SQL Server (Transact-SQL) using the CREATE TABLE statement. It means that the child data is set to their default values when the parent data is deleted or updated. SET DEFAULT It is used in conjunction with ON DELETE or ON UPDATE. It means that the child data is set to NULL when the parent data is deleted or updated. SET NULL It is used in conjunction with ON DELETE or ON UPDATE. It means that the child data is either deleted or updated when the parent data is deleted or updated. CASCADE It is used in conjunction with ON DELETE or ON UPDATE. It means that no action is performed with the child data when the parent data is deleted or updated. NO ACTION It is used in conjunction with ON DELETE or ON UPDATE. You have the options of NO ACTION, CASCADE, SET NULL, or SET DEFAULT. It specifies what to do with the child data when the parent data is updated. The column should either be defined as NULL or NOT NULL and if this value is left blank, the database assumes NULL as the default. column1, column2 The columns that you wish to create in the table. ) child_table The name of the child table that you wish to create. REFERENCES parent_table (parent_col1, parent_col2. The syntax for creating a foreign key with cascade delete using a CREATE TABLE statement in SQL Server (Transact-SQL) is: CREATE TABLE child_tableįOREIGN KEY (child_col1, child_col2. Create Foreign key with cascade delete - Using CREATE TABLE statement Syntax
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