MySQL vs PostgreSQL compared on features, performance, SQL standards, extensions and hosting, with clear guidance on which suits your project.
A practical order of attack for MySQL performance tuning: measure first, fix slow queries and indexes, then tune memory and server settings.
Database replication explained: primary and replica setups, synchronous vs asynchronous copying, replication lag, failover and read scaling.
Database normalization explained with a worked example: turning a messy order spreadsheet into clean tables through 1NF, 2NF and 3NF.
Ten common database design mistakes, from floats for money to missing foreign keys and time zone confusion, with the SQL fix for each one.
A practical data cleansing guide: find duplicate and inconsistent records with SQL, standardise formats, merge safely and stop bad data returning.
Database indexing explained in plain language: how B-tree indexes work, composite and covering indexes, and when an index hurts more than it helps.
SQL vs NoSQL explained: how relational, document, key-value and graph databases differ, and five questions to help you choose the right one.
How to plan a database backup and recovery strategy: RPO and RTO, full and incremental backups, point-in-time recovery, and testing restores.
Database scaling compared: when a bigger server is enough, when to add replicas, caching or partitioning, and why sharding should come last.
Slow query optimization step by step: find the culprits, read the execution plan, and rewrite common SQL anti-patterns that make queries crawl.
