Web Development

SQL & Databases

Relational thinking, querying, joins, aggregation, schema design and indexes, taught against a real database engine rather than through an abstraction over it.

The course project

The Archive Database

A designed, normalised schema with real data loaded, indexed and queried, and every query explained.

course

14 modules · 28 lessons

Each module ends with a practice test, a graded build, and a step of the course project.

Part I: Asking

Tables, Rows and Columns

The relational idea, and why it is not a spreadsheet.

SELECT and WHERE

Choosing columns, then choosing rows.

Order, Limit and Distinct

Arranging results, and the trap in taking the top ten.

NULL

Unknown is not empty, and it is not equal to anything, including itself.

Part II: Combining

Joins

Putting tables back together, and the ways rows quietly vanish.

Outer Joins

When the absence is the answer.

Grouping and Aggregates

Many rows into one number, and the order the clauses actually run in.

Subqueries and CTEs

Queries inside queries, and how to write them so they can be read.

Part III: Building

Changing Data

INSERT, UPDATE, DELETE, and the safety habits that are not optional.

Designing a Schema

Store each fact once, and let the database enforce it.

Part IV: Making It Fast

Indexes

Why a query gets slow, and the one thing that usually fixes it.

Where the ORM Leaks

Going back to Django, now able to read what it writes.

Part V: Confidence

Checking Your Own Queries

The questions to ask before you trust a number a query gave you.

Part VI: Capstone

The Archive Database

Requirements and acceptance criteria. No instructions.

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