Strong Consistency
Problem
Your bank balance changes from: €100 → €20
A subsequent operation must not behave as though the old €100 were still authoritative.
For some data, temporary disagreement is unacceptable.
Solution — Strong Consistency
Coordinate operations so clients observe the required single consistent ordering/state according to the system's consistency model.
Core idea: strong consistency prioritizes a coherent view of state, usually at coordination and availability/latency cost.