The precedence graph turns conflicts into transaction ordering edges.
highlighted = computed this step
The precedence graph
The precedence graph has one node per transaction. An edge appears when an earlier conflicting operation forces one transaction before another. Note: graph edges are recomputed from the schedule order.
precedence graph
Graph from schedule
The graph has 2 nodes and 1 edge. Note: the schedule above and graph below are one compiled scene.
nodes=2,edges=1
conflict-serializability is an exact SUFFICIENT criterion; a cyclic precedence graph is provably not conflict-serializable; view-serializability, lock scheduling, and recovery are beyond these tiny traces - no product claims.
Summary
A precedence graph condenses operation conflicts into transaction ordering constraints. Note: conflict-serializability is exact here; view-serializability, locks, and recovery are deferred.