Do I need (I will ever need) LOCK IN SHARED MODE | FOR UPDATES as part of a transaction?

Question

I'm scared to struggle to figure out how to write code and queries best

directly to the question: do I need or will I ever need to explicitly write LOCK IN SHARED MODEor FOR UPDATEin a transaction (except READ UNCOMMITTED)?

If I have foreign keys, do I need to explicitly select rows to apply lock to these rows or define foreign keys?

Answer 1

Short answer: absolutely yes.

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