Dataford
Interview QuestionsInterview GuidesExperiencesMock InterviewsPricing
Get started
Dataford
Popular roles
Software EngineerData AnalystData ScientistData EngineerBusiness AnalystAI EngineerMachine Learning EngineerProduct Manager
Browse
Browse All RolesEvery role hub, from analyst to MLBrowse All CompaniesCompany-specific interview loopsAll Interview GuidesThe full guide library
Top questions by role
Software EngineerData AnalystData ScientistData EngineerBusiness AnalystAI EngineerMachine Learning EngineerProduct Manager
Top questions by skill
SQLPythonStatisticsMachine LearningA/B TestingSystem DesignGenerative AIProduct SenseMetricsBehavioral
Browse all questions →Try a mock interview
Experiences
Practice
Mock InterviewsTimed interview simulations with feedbackSuccess PathYour 6-week structured planModulesCurated lessons by topicWebinarsTalks from ex-Big Tech data leadsPlaygroundA free-form scratch editor
Learn
BlogInterview strategy and career adviceTech Job Market ReportHiring trends across data and AI rolesFor UniversitiesDataford for career centersAbout DatafordWho we are and how we build
Pricing
Build my plan
Primary Key vs Foreign Key
00:00
5 left

Primary Key vs Foreign Key

EasySQL · PostgreSQL

Problem

What is the difference between a primary key and a foreign key?

Using the provided order table, identify the column serving as the primary key and the column serving as the foreign key. Explain how each key supports data integrity and relationships between tables.

Output

  1. One row per order, with columns order_id and customer_id
  2. Sort by order_id in ascending order

Schema

orders
ColumnTypeDescription
order_idPKINTUnique identifier for each order
customer_idINTIdentifier of the customer associated with the order, referencing customers.customer_id
Tablesorders
Interviewer

Your question is Primary Key vs Foreign Key. Start with the requirements and the one table in the Question tab.

Run and submit as often as you like. When you're ready, talk me through your approach or go straight to the code.

You need to log in / sign up to run or submit.
CodePostgreSQL
Sign up free to run your codeLog inLn 1
Run your query to see results here.