Class: Exwiw::ReverseScope

Inherits:

Object

Object
Exwiw::ReverseScope

show all

Includes:: Serdes

Defined in:: lib/exwiw/reverse_scope.rb

Overview

Opt-in configuration for multi-referencer reverse scoping (see QueryAstBuilder#build_referenced_by_clause).

A global-identity table such as ‘users` carries no scope/tenant column and has no `belongs_to` path of its own to the dump target; many tenant-owned tables instead point at it. The automatic single-referencer reverse extraction only narrows a table referenced by exactly one constrained child — with two or more referencers it falls back to a full dump. `reverse_scope` lets the schema author enumerate the referencers whose own (already-scoped) extraction queries should be UNION’d into the id set this table is constrained to:

<table>.<pk> IN (
  SELECT <ref1>.<col1> FROM <ref1> <ref1 scope> WHERE <col1> IS NOT NULL
  UNION SELECT <ref2>.<col2> FROM <ref2> <ref2 scope> WHERE <col2> IS NOT NULL
  UNION ...
)

It is deliberately explicit — never inferred or emitted by the schema generators, and preserved across regeneration like the other user-owned config (see TableConfig#merge). Only referencers that are themselves scoped belong in ‘via`: an unconstrained referencer would project every row’s id and union the whole table back, defeating the prune (such an arm is skipped with a warning rather than silently widening the dump).