- 1 current stop: learning
- 2 upcoming
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Finish after stop 5
Stop 1 of 5 · Checkout desk at the cycle shop
Trick to keep in mind+3 XP
ACID: all-or-nothing, rules kept, no peeking, survives a crash.
ACID stands for atomicity, consistency, isolation and durability. Atomicity is the part that matters most at a checkout: lowering stock, creating the order and recording the payment either all take effect or none do, so you never end up charged with no order. Eventually consistent stores that accept independent writes give no such promise across several records.
Read it once, then a question tests whether the trick stuck.