[Solved] You wrote this SQL to add a primary key constraint: ALTER TABLE Customers ADD CONSTRAINT PK_Customers PRIMARY KEY (CustomerID);But you get an error saying the constraint name already exists.... | SQL

SQL - Table Constraints

You wrote this SQL to add a primary key constraint:
ALTER TABLE Customers ADD CONSTRAINT PK_Customers PRIMARY KEY (CustomerID);
But you get an error saying the constraint name already exists. What should you do?

AChange PRIMARY KEY to UNIQUE

BRename the constraint to a unique name and try again

CDrop the Customers table

DRemove the CONSTRAINT keyword

Step-by-Step Solution

Solution:

Step 1: Understand the error cause
The error indicates the constraint name PK_Customers is already used in the database.
Step 2: Fix by renaming the constraint
Choose a different, unique constraint name and run the command again.
Final Answer:
Rename the constraint to a unique name and try again -> Option B
Quick Check:
Unique constraint names avoid errors = D [OK]

Quick Trick: Use unique names for constraints to avoid conflicts [OK]

Common Mistakes:

MISTAKES

Removing CONSTRAINT keyword
Dropping tables unnecessarily
Changing constraint type incorrectly

Master "Table Constraints" in SQL

9 interactive learning modes - each teaches the same concept differently

Learn Why Deep Visual Try Challenge Project Recall Time

More SQL Quizzes

You wrote this SQL to add a primary key constraint:

Step 1: Understand the error cause

Step 2: Fix by renaming the constraint

Final Answer:

Quick Check:

Want More Practice?