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5 articles tagged #SQL.
P.01Two requests try to update the same row at the same time. Pessimistic locking stops one of them from starting; optimistic locking lets both run and catches the conflict at the end. Here's how each works, with real SQL, and how to pick.
P.02Soft delete keeps a deleted_at column and hides rows instead of removing them. It sounds like the safe default, but it quietly breaks unique constraints, foreign keys, and query performance if you don't design for it up front. Here's the real tradeoff.
P.03dbt turns SQL SELECT statements into a tested, documented, version-controlled data pipeline. Here's how it works and when you should add it to your data stack.
P.04Running totals, rankings, moving averages, lag and lead comparisons: window functions handle the analytics queries that would otherwise require application-side loops or multiple round-trips. Here's how they work.
P.05EditorPickMaster SQL from basics to advanced — SELECT, JOIN, GROUP BY, ORDER BY, indexes, date functions, and more using SQLite with Python.