Free online courseDatabase Systems: SQL, Indexing, Query Optimization, Transactions and Distributed Databases

Course Description

Database Systems: SQL, Indexing, Query Optimization, Transactions and Distributed Databases is a free online course in the Technology and Programming category, focused on modern database fundamentals and real-world system design. It guides you from the relational model and practical SQL to the internal mechanics that make databases fast, reliable, and scalable.

You will explore how data is stored and accessed, including file layouts, log-structured merge trees, and the tradeoffs between row and column storage with compression considerations. The course also covers memory and core data structures such as hash tables, then moves into indexing techniques like B-trees as well as vector and inverted indexes, filters, and tries, including how indexes behave under concurrent workloads.

On the query side, it digs into sorting, join algorithms, and query execution, then explains how optimizers plan efficient strategies. You will learn the theory and practice of concurrency control, including two-phase locking, optimistic methods, and multi-version concurrency control, with a strong focus on correctness and performance.

Reliability topics include logging and recovery, including ARIES-style recovery principles. Finally, the course expands to distributed databases, covering architectures, distributed transactional systems, distributed analytics, and how modern platforms and warehouses fit into the broader landscape. Ideal for learners aiming to strengthen SQL skills and understand what happens beneath the surface of database engines.