Class: ActiveRecord::Refined::AST::JsonKeys

Inherits:

Node

• Object
• Node
• ActiveRecord::Refined::AST::JsonKeys

Includes:

ComputedJson, JsonComparable, Predications

Defined in:

lib/active_record/refined/ast.rb

Overview

The keys of a JSON document, as Hash#keys gives them: a JSON array. Only the MySQL family has a function for it; the other two reach the same array through a subquery over their key-listing functions. The type guard is what makes all four answer alike: the keys of what is not an object are NULL rather than SQLite's array indices or PostgreSQL's error, and the keys of {} are [] rather than PostgreSQL's NULL, jsonb_agg over no rows.

Instance Attribute Summary

• #operand ⇒ Object readonly

  Returns the value of attribute operand.

Instance Method Summary

• #initialize(operand) ⇒ JsonKeys constructor

  A new instance of JsonKeys.

• #to_arel(table, model) ⇒ Object

Methods included from ComputedJson

#json_value?

Methods included from JsonComparable

#between?, #in?, #not_between?, #not_in?, #~

Methods included from Predications

#!=, #!~, #<, #<=, #==, #=~, #>, #>=, #between?, #bury, #casecmp?, #contains?, #dig, #dig_text, #distinct_from?, #end_with?, #except, #false?, #ilike?, #in?, #include?, #intersect?, #key?, #keys, #like?, #member?, #not_between?, #not_distinct_from?, #not_false?, #not_ilike?, #not_in?, #not_like?, #not_null?, #not_true?, #null?, #start_with?, #subset?, #superset?, #true?, #when

Methods inherited from Node

#as, #asc, #desc

Constructor Details

#initialize(operand) ⇒ JsonKeys

Returns a new instance of JsonKeys.

# File 'lib/active_record/refined/ast.rb', line 1073

def initialize(operand)
  @operand = operand
end

Instance Attribute Details

#operand ⇒ Object (readonly)

Returns the value of attribute operand.

# File 'lib/active_record/refined/ast.rb', line 1071

def operand
  @operand
end

Instance Method Details

#to_arel(table, model) ⇒ Object

# File 'lib/active_record/refined/ast.rb', line 1077

def to_arel(table, model)
  document = to_arel_operand(operand, table, model)
  case AST.adapter_family(model)
  when :sqlite
    sql = compile(document, model)
    Arel.sql("CASE WHEN json_type(#{sql}) = 'object' " \
             "THEN (SELECT json_group_array(key) FROM json_each(#{sql})) END")
  when :postgresql
    sql = compile(document, model)
    Arel.sql("CASE WHEN jsonb_typeof(#{sql}) = 'object' " \
             "THEN COALESCE((SELECT jsonb_agg(k) FROM jsonb_object_keys(#{sql}) k), " \
             "CAST('[]' AS jsonb)) END")
  else
    Arel::Nodes::NamedFunction.new("JSON_KEYS", [document])
  end
end