Which SQL command correctly creates a foreign key constraint to enforce referential integrity between Orders and Customers tables?

easy📝 Syntax Q3 of 15

SQL - Table Relationships

Which SQL command correctly creates a foreign key constraint to enforce referential integrity between Orders and Customers tables?

AALTER TABLE Orders ADD CONSTRAINT fk_customer FOREIGN KEY (CustomerID) REFERENCES Customers(CustomerID);

BCREATE TABLE Orders (OrderID INT, CustomerID INT, FOREIGN KEY CustomerID REFERENCES Customers);

CALTER TABLE Customers ADD FOREIGN KEY (CustomerID) REFERENCES Orders(OrderID);

DCREATE FOREIGN KEY Orders(CustomerID) REFERENCES Customers(CustomerID);

Step-by-Step Solution

Solution:

Step 1: Identify the correct syntax for adding a foreign key
The correct syntax uses ALTER TABLE with ADD CONSTRAINT and specifies the foreign key column and referenced table and column.
Step 2: Verify the referenced table and column
Orders.CustomerID references Customers.CustomerID, which matches the foreign key relationship.
Final Answer:
ALTER TABLE Orders ADD CONSTRAINT fk_customer FOREIGN KEY (CustomerID) REFERENCES Customers(CustomerID); -> Option A
Quick Check:
Check syntax correctness and referenced columns [OK]

Quick Trick: Use ALTER TABLE ADD CONSTRAINT for foreign keys [OK]

Common Mistakes:

MISTAKES

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