primary key foreign key example ms sql server
Example 1: mysql add foreign key
CREATE TABLE tableName (
ID INT,
SomeEntityID INT,
PRIMARY KEY (ID),
FOREIGN KEY (SomeEntityID)
REFERENCES SomeEntityTable(ID)
ON DELETE CASCADE
);
ALTER TABLE
tableName
ADD
FOREIGN KEY (SomeEntityID) REFERENCES SomeEntityTable(ID) ON DELETE CASCADE;
ALTER TABLE
tableName
ADD CONSTRAINT fk_name
FOREIGN KEY (SomeEntityID) REFERENCES SomeEntityTable(ID) ON DELETE CASCADE;
Example 2: alter table add column forigen key mysql
ALTER TABLE tryholpz_demo07.core_modules
ADD COLUMN belongs_to_role INT,
ADD FOREIGN KEY core_modules(belongs_to_role) REFERENCES role_specific_modules_info(id) ON DELETE CASCADE
Example 3: foreign key mssql
CREATE TABLE Sales.TempSalesReason
(
TempID int NOT NULL, Name nvarchar(50)
, CONSTRAINT PK_TempSales PRIMARY KEY NONCLUSTERED (TempID)
, CONSTRAINT FK_TempSales_SalesReason FOREIGN KEY (TempID)
REFERENCES Sales.SalesReason (SalesReasonID)
ON DELETE CASCADE
ON UPDATE CASCADE
)
;