Practice Primary Key Constraint (4.2.2.1) - Structured Query Language (SQL) - Part 1
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PRIMARY KEY Constraint

Practice - PRIMARY KEY Constraint

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Practice Questions

Test your understanding with targeted questions

Question 1 Easy

What is the purpose of a PRIMARY KEY in a database table?

💡 Hint: Think about why we need unique identifiers.

Question 2 Easy

Can a column defined as a primary key contain NULL values?

💡 Hint: Consider the requirement for uniqueness.

4 more questions available

Interactive Quizzes

Quick quizzes to reinforce your learning

Question 1

What does a PRIMARY KEY ensure in a database?

Duplicates are allowed
Each record is unique
NULL values are permissible

💡 Hint: Consider the nature of keys in databases.

Question 2

True or False: A table can have multiple primary keys.

True
False

💡 Hint: Think about the definition of a primary key.

2 more questions available

Challenge Problems

Push your limits with advanced challenges

Challenge 1 Hard

Design a database schema for a university that includes at least two tables where one table's primary key is referenced as a foreign key in another. Ensure you explain why the primary keys are essential in your design.

💡 Hint: Think about relationships in your schema.

Challenge 2 Hard

Given a dataset with duplicate entries and missing data, how would you utilize primary key constraints to clean up the data and what implications would that have?

💡 Hint: Consider how primary keys enforce uniqueness.

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Reference links

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