4 — Databases, Storage & the Data Layer

D A TA L A Y E R M A S T E R C L A S S Databases and the Data Layer: Relational, Document and Vector Modelling, indexing, transactions, engines, vector search and the operational layer around them. By Md Ahbab Hamid Khan

What this deck assumes about you • You write code in at least one language and ship it • You are comfortable with functions, classes and async work • You know HTTP request and response semantics • You use Git and understand branching and merging • You have written some SQL, even if only SELECT statements • You have never needed to reason about isolation levels Getting started 2

Agenda and how to use this deck # Section What you take away 1 Modelling and schema design Entities, 3NF, denormalisation, keys, constraints 2 Indexes, plans and transactions B-trees, composite order, EXPLAIN, isolation levels 3 Relational engines Postgres, MySQL, SQLite, and the commercial pair 4 Document and key-value stores Mongo modelling, Redis cache, locks and queues 5 Managed platforms Supabase end to end, RLS, and Firebase contrasted 6 Vector databases Embeddings, ANN indexing, hybrid search, seven tools 7 Access layer and operations ORMs, migrations, backups, scaling, OLTP versus OLAP Getting started 3