OptionalextraProvider-specific extra data (e.g. overlapping-change data for ISA propagation)
The complete SQL to execute (may include record-change tracking, temp tables, etc.)
OptionalparametersParameterized query values (e.g. [$1,$2] for PG). Null/undefined for inline SQL.
OptionalsimpleSimpler SQL without record-change wrapping, used for logging/migration replay
Result of save SQL generation. Subclasses populate this from their dialect-specific SQL generators (stored procedure calls, function calls, etc.).