How Databases Work
The database system map -- 25 lessons connecting the framework-neutral mental model (data, tables, keys, relationships, transactions), a fair SQL vs NoSQL landscape, database design skill, security fundamentals, and the AI/vector-database distinction, with pointers to this site's SQL, PostgreSQL, MongoDB, and Redis tutorials for hands-on depth.
25 Lessons · 610 min · Learning Platform Editorial Team
What you need on the desk
- None strictly required -- every concept is taught through diagrams, tables, and prose
- Optionally the SQL/PostgreSQL/MongoDB/Redis tutorials open alongside, for hands-on depth on any product
- A Node.js environment, to run the small JavaScript decision/schema-check examples
Know this much before you start
- None -- this course assumes no prior database experience and is the recommended starting point before SQL, PostgreSQL, MongoDB, or Redis.
- This course teaches the SYSTEM MAP -- how databases work conceptually and how to choose between them -- not SQL syntax or any single product's hands-on usage. Deep syntax and tool skills live in this site's dedicated tutorials, linked from the relevant lesson.
- Helpful but not required: basic comfort with the idea that applications store and retrieve data.
By the end, you can
- Explain what a database is and clearly distinguish database, backend, and API
- Explain tables, primary keys, foreign keys, and one-to-one/one-to-many/many-to-many relationships without writing a single query
- Explain constraints, normalization, indexing tradeoffs, and transactions/ACID as concepts that apply across any relational database
- Fairly compare SQL and NoSQL data models (relational, document, key-value) and know when each tends to fit
- Place SQLite, MySQL, PostgreSQL, MongoDB, Redis, and Supabase on one landscape and know which existing course to continue to for hands-on depth
- Design a database schema from requirements: identify entities, choose keys, define relationships, add constraints, and design around real access patterns
- Explain database security fundamentals (least privilege, parameterized queries, row-level security, secrets, backups) at a vendor-neutral level
- Distinguish a relational database from a vector database and explain where each fits in an AI/RAG application