Choosing the right database

Stage 2 · Lesson 1 of 6

What a relational database gives you

Relational databases: the sensible default

A stores data in tables of rows and columns and links tables with keys: an order row holds customer_id 42 rather than a copy of the customer. On top of that it gives you four things most apps need. let you combine tables to answer new questions without changing how data is stored.

such as NOT NULL, UNIQUE and foreign keys make the database refuse bad data. make a group of changes all succeed or all fail. And SQL, a standard query language, works across , MySQL, SQL Server and SQLite with small differences. These features stop whole classes of bugs before they reach users.

Common trapskipping constraints "for flexibility" and then cleaning duplicate and orphaned rows by hand for months.

A question to check yourself, an AI practice session and 2 cheat sheet entries come with the full roadmap. Unlock

Resources for this stage

Start with· follow one of these

  • CoursePaid
    Grokking Relational Database Design and Modeling

    Design Gurus · Intermediate · $98 one-time

    Data modelling, ER diagrams, keys and normalisation for the relational default, with worked designs

  • GuideFree
    PostgreSQL Tutorial

    PostgreSQL Global Development Group · Beginner

    The short official tutorial: create a database, tables and your first queries in an evening

Practise

  • db<>fiddle

    Run SQL on PostgreSQL, MySQL or SQLite in the browser and compare how each handles JSON

  • SQLBolt

    Free interactive lessons if your SQL needs warming up before the hands-on task

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