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Design a Database Schema and Write 5 Useful SQL Queries

The capstone project for Database Design for Beginners — a free Data & Tech course. Pass it and you earn a certificate anyone can verify.

Start the course free Download the project workbook

The project unlocks once you complete the lessons. The workbook is free to download now so you can see exactly what is expected.

What you will submit

A shared link (Google Doc, GitHub README, Notion, or dbdiagram.io) containing: a short app description, a schema of at least 4 tables with data types and key constraints, clearly marked relationships including at least one many-to-many junction table, and 5 working SQL queries (with a SELECT+WHERE, an INSERT, an UPDATE/DELETE with WHERE, and a JOIN), each explained in plain English.

What to do, step by step

  1. Pick ONE real or sample app to model — a shop, a school, a clinic, a church/NGO membership system, or a small delivery service. Write one or two sentences describing what it does and the main 'things' it tracks, so your design has a clear purpose (Lesson 1).
  2. Design the schema as a table list or ER-style diagram (boxes and lines on paper, draw.io, or dbdiagram.io). Include at least FOUR tables, and for each table list its columns with a sensible data type for every column and the key constraints — mark the PRIMARY KEY and any NOT NULL, UNIQUE, or DEFAULT (Lessons 2 and 4). Remember to store phone/account numbers as VARCHAR and money as DECIMAL.
  3. Show the relationships clearly: mark every FOREIGN KEY and state whether each relationship is one-to-many or many-to-many. Your design MUST include at least one many-to-many relationship handled with a junction table (for example order_items, or student_subjects) as taught in Lesson 3.
  4. Make sure your design is normalised: no customer name or product price repeated across rows that should only hold an ID pointer, one value per cell, and each column describing the thing its table is about (Lesson 5). Add a one-line note explaining one duplication you removed and why.
  5. Write FIVE useful SQL queries against your schema that answer real business questions. Include at least: one SELECT with a WHERE filter, one INSERT, one UPDATE or DELETE that correctly uses a WHERE, and at least one JOIN across two tables (Lessons 6 and 7). Above each query, write a short comment saying in plain English what question it answers.
  6. Put it all together in one document or shared link (Google Doc, GitHub repo/README, Notion, or a dbdiagram.io share link): the app description, the table list/diagram with keys and relationships, and the five queries with their plain-English explanations. Submit that single link.

Files to work with

Project workbook (fill in, then submit)The whole brief, an evidence checklist, the grading rubric as a self-check and the link-sharing steps in one file. Opens in Word, Google Docs or WPS.Word · 7 KB

How it is graded

CriterionWeight
Schema design: at least 4 well-chosen tables, each with a clear primary key and a sensible data type for every column (VARCHAR for phone/account numbers, DECIMAL for money), reflecting one focused 'thing' per table25%
Relationships: all foreign keys are correctly placed and labelled, relationship types (one-to-many / many-to-many) are stated, and at least one many-to-many is correctly handled with a junction table25%
Normalisation and constraints: no error-prone duplication (IDs used instead of repeated names/prices), one value per cell, sensible NOT NULL/UNIQUE/DEFAULT constraints, and a note on one duplication removed20%
SQL queries: five queries that run against the schema and answer real questions, including a SELECT with WHERE, an INSERT, an UPDATE or DELETE that uses a WHERE, and at least one correct JOIN matching a foreign key to a primary key20%
Clarity and presentation: a clear app description, readable diagram/table list, and a plain-English explanation above each query, all in one accessible shared link10%

You need 65% overall to pass. A failed submission comes back with feedback and can be revised and resubmitted.

Before you submit: make your link public

If your work lives in Google Drive or Google Docs, open Share → General access and change “Restricted” to “Anyone with the link” (Viewer). Then paste the link into a private browser window: if it opens without sign-in, you are ready. A private link cannot be graded — it is the single most common reason a good project fails.

Frequently asked questions

Do I have to finish Database Design for Beginners before submitting the project?

Yes. The submission screen opens once every lesson in Database Design for Beginners is marked complete. The lessons are where the methods, the Nigerian context and the worked examples the project depends on are taught.

How is the project graded?

An examiner scores each rubric criterion from 0 to 100 and weights them as shown on this page; you need 65% overall to pass. Most submissions are graded within minutes and you get written feedback on what was strong and what to improve.

Can I resubmit if I fail?

Yes. A failed project comes back with feedback; revise the weak parts and resubmit. A passed project is final — the certificate is issued and cannot be re-rolled.

What do I actually submit?

A write-up of what you did (under 5,000 characters) plus a public link to your work — a Google Drive folder, Google Doc, spreadsheet, GitHub repository or video. The link must open without sign-in; a private link cannot be graded. The free project workbook on this page walks you through all 6 steps.

Is the certificate real?

Yes. Passing this project issues a certificate with a unique verification code. Anyone — an employer, a client, a school — can open the verification page and see that the certificate is genuine and which project earned it.

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Database Design for Beginners is free and self-paced. Finish the lessons, complete this project, and the certificate is yours to share.

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