Class: Exwiw::QueryAst::UnionSubquery

Inherits:
Struct
  • Object
show all
Defined in:
lib/exwiw/query_ast.rb

Overview

A subquery that UNIONs several single-column ‘Select`s into one id set. Used by multi-referencer reverse / “referenced_by” extraction (TableConfig#reverse_scope): a parent table referenced by many scoped tables is constrained to the union of every referencer’s projected foreign key, rather than falling back to dumping every row:

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

Each ‘queries` element is a `Select` already projected to the foreign-key column that points at the parent (with a NULL-excluding filter).

Instance Attribute Summary collapse

Instance Method Summary collapse

Instance Attribute Details

#queries ⇒ Object

Returns the value of attribute queries

Returns:

  • (Object) —

    the current value of queries



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101
 
# File 'lib/exwiw/query_ast.rb', line 99

def queries
  @queries
end

Instance Method Details

#to_h ⇒ Object 



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# File 'lib/exwiw/query_ast.rb', line 100

def to_h
  { union: queries.map(&:to_h) }
end