Isolation Levels

Honest by Construction

Expected facts are assertions only; the matrix compiler is the source of truth.

highlighted = computed this step

Honest by construction

The lesson source compiles the matrix, turns recomputed facts into expected assertions, and compiles again. Wrong assertions and derived sidecars fail before render.

recompute before render\text{recompute before render}

Guarded compiled facts

The guarded matrix has 4 levels and 3 stronger-than cover edges. Both facts come from the compiled output.

levels=4,cover edges=3\text{levels}=4,\quad \text{cover edges}=3

isolation levels are rendered as a tiny pedagogical matrix over named anomalies only; ANSI completeness, vendor behavior, performance, and operational guarantees are out of scope.

Guarded matrixleveldirty_readnon_repeatable_readlost_updatewrite_skewread_committedblockedallowedallowedallowedrepeatable_readblockedblockedallowedallowedsnapshot_isolationblockedblockedblockedallowedserializableblockedblockedblockedblocked blocked versus allowedlevelblockedCountblockedallowedCountallowedread_committed1dirty_read3non_repeatable_read, lost_update, write_skewrepeatable_read2dirty_read, non_repeatable_read2lost_update, write_skewsnapshot_isolation3dirty_read, non_repeatable_read, lost_update1write_skewserializable4dirty_read, non_repeatable_read, lost_update, write_skew0none stronger-than cover edgesstrongerweakerrepeatable_readread_committedsnapshot_isolationrepeatable_readserializablesnapshot_isolation

Summary

The page shows only matrix facts that survive the compile boundary. Note: the model remains a tiny pedagogical synthesis, not vendor guidance.

honest isolation matrix render\text{honest isolation matrix render}