Which SQL statement correctly adds a foreign key to establish a one-to-many relationship from Invoices to Clients?

easy📝 Syntax Q3 of 15

SQL - Table Relationships

Which SQL statement correctly adds a foreign key to establish a one-to-many relationship from Invoices to Clients?

ACREATE TABLE Invoices (InvoiceID INT PRIMARY KEY, ClientID INT, FOREIGN KEY ClientID REFERENCES Clients(ClientID));

BALTER TABLE Clients ADD FOREIGN KEY (InvoiceID) REFERENCES Invoices(InvoiceID);

CCREATE TABLE Clients (ClientID INT PRIMARY KEY, InvoiceID INT FOREIGN KEY REFERENCES Invoices(InvoiceID));

DALTER TABLE Invoices ADD FOREIGN KEY (ClientID) REFERENCES Clients(ClientID);

Step-by-Step Solution

Solution:

Step 1: Identify the child table
Invoices is the child table referencing Clients.
Step 2: Correct syntax for foreign key
ALTER TABLE Invoices ADD FOREIGN KEY (ClientID) REFERENCES Clients(ClientID); uses ALTER TABLE on Invoices to add a foreign key referencing Clients, which is correct.
Final Answer:
ALTER TABLE Invoices ADD FOREIGN KEY (ClientID) REFERENCES Clients(ClientID); -> Option D
Quick Check:
Foreign key goes in child table referencing parent [OK]

Quick Trick: Foreign key in child table referencing parent primary key [OK]

Common Mistakes:

MISTAKES

Master "Table Relationships" in SQL

9 interactive learning modes - each teaches the same concept differently

Want More Practice?

15+ quiz questions · All difficulty levels · Free

More SQL Quizzes