Why CQRS Leads To Event Sourcing

CQRS separates command decisions from query views. The hard part is not the split; it is reliable synchronization from writes to reads.

Reasoning Chain

1. Commands change business facts, not just tables.

2. Read models need derived state that often cannot be reconstructed safely from row triggers alone.

3. Polling creates latency, missed intent, ordering ambiguity, and scaling pressure.

4. Updating the write store and read store in one use case creates a double-commit problem.

5. Durable domain events solve this by recording what happened once and projecting it many times.

Caveats

• CQRS can be partial; non-CQRS areas can keep a unified model.