Db2 FOREIGN KEY constraint syntax The following illustrates the syntax of defining a foreign key constraint: [CONSTRAINT constraint_name] FOREIGN KEY (fk1, fk2,...)

A foreign key references a primary key or a unique key in the same or another table. A foreign key assignment indicates that referential integrity is to be maintained according to the specified referential constraints.

To define a foreign key, use one of the following approaches: Issue a CREATE TABLE statement and specify a FOREIGN KEY clause. Choose a constraint name for the relationship that is defined by a foreign key.

Foreign key constraints (also known as referential constraints or referential integrity constraints) enable definition of required relationships between and within tables. For example, a typical foreign key constraint might state that every employee in the EMPLOYEE table must be a member of an existing department, as defined in the DEPARTMENT ...

Dec 17, 2019 · A foreign key specifies that a column in one table refers to the primary key of another table. The key point is that the column must be defined in the referencing table -- as well as the referenced table.

Similar to the unique constraints, you can use a primary key and a foreign key constraint to declare relationships between multiple tables. Syntax: db2 create table <tab_name>(,.., primary key ()) Example: To create salesboys table with sid as a primary key

Apr 30, 2025 · Learn how to create a table in Db2 with foreign key constraints, highlighting differences between candidate keys and composite keys. To create a table with a foreign key constraint in DB2, you need to define the relationship between the tables involved.

Apr 30, 2025 · To create a foreign key constraint in DB2, you can use the CREATE TABLE statement or the ALTER TABLE statement. Here’s a basic example of how to define a foreign key when creating a table: CREATE TABLE orders ( order_id INT PRIMARY KEY, user_id INT, FOREIGN KEY (user_id) REFERENCES customers(id) );

Examples - Defining a Foreign Key on a Table. EMPLOYEE: Creates a table named EMPLOYEE. DEPT_ID: Defines DEPT_ID as a foreign key, referencing DEPT_ID in the DEPARTMENT table. ON DELETE CASCADE: Ensures that if a department is deleted in DEPARTMENT, all employees associated with that department in EMPLOYEE are also deleted.

Apr 11, 2025 · To define a foreign key constraint in DB2, you can use the following SQL syntax: order_id INT PRIMARY KEY, user_id INT, FOREIGN KEY (user_id) REFERENCES customers(id) In this example, the user_id column in the orders table is a foreign key that references the id column in the customers table.