Class: JsonApiPgSql

Inherits:
Object
  • Object
show all
Defined in:
lib/active_model_serializers/adapter/json_api_pg.rb

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(base_serializer, base_relation, instance_options, options) ⇒ JsonApiPgSql

Returns a new instance of JsonApiPgSql.



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# File 'lib/active_model_serializers/adapter/json_api_pg.rb', line 384

def initialize(base_serializer, base_relation, instance_options, options)
  @base_relation = base_relation
  @instance_options = instance_options
  @options = options

  # Make a JsonThing for everything,
  # cached as the full_name:

  # Watch out: User.where is a Relation, but plain User is not:
  ar_class = ActiveRecord::Relation === base_relation ? base_relation.klass : base_relation

  case base_serializer
  when ActiveModel::Serializer::CollectionSerializer
    ActiveModelSerializers::Adapter::JsonApiPg.warn_about_collection_serializer
    base_serializer = base_serializer.element_serializer
    @many = true
  when ActiveModelSerializersPg::CollectionSerializer
    base_serializer = base_serializer.element_serializer
    @many = true
  else
    base_serializer = base_serializer.class
    @many = false
  end
  base_serializer ||= ActiveModel::Serializer.serializer_for(ar_class.new, options)
  @base_serializer = base_serializer

  base_name = ar_class.name.underscore.pluralize
  base_thing = JsonThing.new(ar_class, base_name, base_serializer, options)
  @fields_for = {}
  @attribute_fields_for = {}
  @reflection_fields_for = {}
  @json_things = {
    base: base_thing, # `base` is a sym but every other key is a string
  }
  @json_things[base_name] = base_thing
  # We don't need to add anything else to @json_things yet
  # because we'll lazy-build it via get_json_thing.
  # That lets us go as deep in the relationships as we need
  # without loading anything extra.
end

Instance Attribute Details

#base_relation ⇒ Object (readonly)

Returns the value of attribute base_relation.



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# File 'lib/active_model_serializers/adapter/json_api_pg.rb', line 373

def base_relation
  @base_relation
end

#base_serializer ⇒ Object (readonly)

Returns the value of attribute base_serializer.



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# File 'lib/active_model_serializers/adapter/json_api_pg.rb', line 373

def base_serializer
  @base_serializer
end

Class Method Details

.json_column_type ⇒ Object 



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# File 'lib/active_model_serializers/adapter/json_api_pg.rb', line 375

def self.json_column_type
  # These classes may not exist, depending on the Rails version:
  @@json_column_type = if Rails::VERSION::STRING >= '5.2'
                         'ActiveRecord::Type::Json'
                       else
                         'ActiveRecord::ConnectionAdapters::PostgreSQL::OID::Json'
                       end.constantize
end

Instance Method Details

#_attribute_fields_for(resource) ⇒ Object 



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# File 'lib/active_model_serializers/adapter/json_api_pg.rb', line 779

def _attribute_fields_for(resource)
  attrs = Set.new(serializer_attributes(resource))
  # JSON:API always excludes the `id`
  # even if it's part of the serializer:
  attrs = attrs - [resource.primary_key.to_sym]
  fields_for(resource).select { |f| attrs.include? f }.to_a
end

#_fields_for(resource) ⇒ Object 



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# File 'lib/active_model_serializers/adapter/json_api_pg.rb', line 759

def _fields_for(resource)
  # Sometimes options[:fields] has plural keys and sometimes singular,
  # so try both:
  resource_key = resource.json_type.to_sym
  fields = @instance_options.dig :fields, resource_key
  if fields.nil?
    resource_key = resource.json_type.singularize.to_sym
    fields = @instance_options.dig :fields, resource_key
  end
  if fields.nil?
    # If the user didn't request specific fields, then give them all that appear in the serializer:
    fields = serializer_attributes(resource).to_a + serializer_reflections(resource).to_a
  end
  fields
end

#_reflection_fields_for(resource) ⇒ Object 



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# File 'lib/active_model_serializers/adapter/json_api_pg.rb', line 791

def _reflection_fields_for(resource)
  refls = Set.new(serializer_reflections(resource))
  fields_for(resource).select { |f| refls.include? f }.to_a
end

#attribute_fields_for(resource) ⇒ Object 



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# File 'lib/active_model_serializers/adapter/json_api_pg.rb', line 775

def attribute_fields_for(resource)
  @attribute_fields_for[resource.full_name] ||= _attribute_fields_for(resource)
end

#base_resource ⇒ Object 



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# File 'lib/active_model_serializers/adapter/json_api_pg.rb', line 704

def base_resource
  @json_things[:base]
end

#column_is_castable_to_jsonb?(column_class) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/active_model_serializers/adapter/json_api_pg.rb', line 498

def column_is_castable_to_jsonb?(column_class)
  column_class.is_a?(ActiveRecord::ConnectionAdapters::PostgreSQL::OID::Hstore) or
    column_class.is_a?(self.class.json_column_type)
end

#column_is_castable_to_jsonb_array?(column_class) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/active_model_serializers/adapter/json_api_pg.rb', line 503

def column_is_castable_to_jsonb_array?(column_class)
  column_class.is_a?(ActiveRecord::ConnectionAdapters::PostgreSQL::OID::Array) and
    column_is_castable_to_jsonb?(column_class.subtype)
end

#column_is_jsonb?(column_class) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/active_model_serializers/adapter/json_api_pg.rb', line 489

def column_is_jsonb?(column_class)
  column_class.is_a? ActiveRecord::ConnectionAdapters::PostgreSQL::OID::Jsonb
end

#column_is_jsonb_array?(column_class) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/active_model_serializers/adapter/json_api_pg.rb', line 493

def column_is_jsonb_array?(column_class)
  column_class.is_a?(ActiveRecord::ConnectionAdapters::PostgreSQL::OID::Array) and
    column_class.subtype.is_a?(ActiveRecord::ConnectionAdapters::PostgreSQL::OID::Jsonb)
end

#fields_for(resource) ⇒ Object 



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# File 'lib/active_model_serializers/adapter/json_api_pg.rb', line 755

def fields_for(resource)
  @fields_for[resource.full_name] ||= _fields_for(resource)
end

#get_json_thing(resource, field) ⇒ Object 



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# File 'lib/active_model_serializers/adapter/json_api_pg.rb', line 425

def get_json_thing(resource, field)
  refl_name = "#{resource.full_name}.#{field}"
  @json_things[refl_name] ||= resource.from_reflection(field)
end

#get_json_thing_from_base(field) ⇒ Object

Takes a dotted field name (not including the base resource) like we might find in options, and builds up all the JsonThings needed to get to the end.



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# File 'lib/active_model_serializers/adapter/json_api_pg.rb', line 672

def get_json_thing_from_base(field)
  r = base_resource
  field.split('.').each do |f|
    r = get_json_thing(r, f)
  end
  r
end

#include_cte(resource) ⇒ Object

See note in _jbs_name method for why we split each thing into two CTEs.



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# File 'lib/active_model_serializers/adapter/json_api_pg.rb', line 640

def include_cte(resource)
  parent = resource.parent
  "    SELECT  DISTINCT ON (\"\#{resource.table_name}\".\"\#{resource.primary_key}\")\n            \"\#{resource.table_name}\".*\n    FROM    \"\#{resource.table_name}\"\n    JOIN    \"\#{parent.cte_name}\"\n    ON      \#{include_cte_join_condition(resource)}\n    ORDER BY \"\#{resource.table_name}\".\"\#{resource.primary_key}\"\n  EOQ\nend\n"

#include_cte_join_condition(resource) ⇒ Object 



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# File 'lib/active_model_serializers/adapter/json_api_pg.rb', line 628

def include_cte_join_condition(resource)
  parent = resource.parent
  if resource.belongs_to?
    %Q{"#{parent.cte_name}"."#{resource.foreign_key}" = "#{resource.table_name}"."#{resource.primary_key}"}
  elsif resource.has_many? or resource.has_one?
    %Q{"#{parent.cte_name}"."#{parent.primary_key}" = "#{resource.table_name}"."#{resource.foreign_key}"}
  else
    raise "not supported relationship: #{resource.full_name}"
  end
end

#include_ctes ⇒ Object 



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# File 'lib/active_model_serializers/adapter/json_api_pg.rb', line 680

def include_ctes
  includes.map { |inc|
    # Be careful: inc might have dots:
    th = get_json_thing_from_base(inc)
    "      \"\#{th.cte_name}\" AS (\n        \#{include_cte(th)}\n      ),\n    EOQ\n  }.join(\"\\n\")\nend\n"

#include_jbs(resource) ⇒ Object

See note in _jbs_name method for why we split each thing into two CTEs.



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# File 'lib/active_model_serializers/adapter/json_api_pg.rb', line 653

def include_jbs(resource)
  "    SELECT  \"\#{resource.table_name}\".*,\n            \#{select_resource(resource)} AS j\n    FROM    \"\#{resource.cte_name}\" AS \"\#{resource.table_name}\"\n    \#{join_resource_relationships(resource)}\n  EOQ\nend\n"

#include_jbsses ⇒ Object 



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# File 'lib/active_model_serializers/adapter/json_api_pg.rb', line 692

def include_jbsses
  includes.map { |inc|
    # Be careful: inc might have dots:
    th = get_json_thing_from_base(inc)
    "      \"\#{th.jbs_name}\" AS (\n        \#{include_jbs(th)}\n      ),\n    EOQ\n  }.join(\"\\n\")\nend\n"

#include_selects ⇒ Object 



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# File 'lib/active_model_serializers/adapter/json_api_pg.rb', line 616

def include_selects
  @include_selects ||= includes.map {|inc|
    th = get_json_thing_from_base(inc)
    # TODO: UNION ALL would be faster than UNION,
    # but then we still need to de-dupe when we have two paths to the same table,
    # e.g. buyer and seller for User.
    # But we could group those and union just them, or even better do a DISTINCT ON (id).
    # Since we don't get the id here that could be another CTE.
    %Q{UNION SELECT j FROM "#{th.jbs_name}"}
  }
end

#includes ⇒ Object 



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# File 'lib/active_model_serializers/adapter/json_api_pg.rb', line 662

def includes
  @includes ||= (@instance_options[:include] || []).sort_by do |inc|
    # Sort these by length so we never have bad foreign references in the CTEs:
    inc.size
  end
end

#join_resource_relationships(resource) ⇒ Object 



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# File 'lib/active_model_serializers/adapter/json_api_pg.rb', line 551

def join_resource_relationships(resource)
  fields = reflection_fields_for(resource)
  fields.map{|f|
    child_resource = get_json_thing(resource, f)
    refl = child_resource.reflection
    if refl.has_many?
      if refl.ar_reflection.present?
        # Preserve ordering options, either from the AR association itself
        # or from the class's default scope.
        # TODO: preserve the whole custom relation, not just ordering
        p = refl.ar_class.new
        ordering = p.send(refl.name).arel.orders
        ordering = child_resource.ar_class.default_scoped.arel.orders if ordering.empty?
        ordering = ordering.map{|o|
          case o
          # TODO: The gsub is pretty awful....
          when Arel::Nodes::Ordering
            o.to_sql.gsub("\"#{child_resource.table_name}\"", "rel")
          when String
            o
          else
            raise "Unknown type of ordering: #{o.inspect}"
          end
        }.join(', ').presence
        ordering = "ORDER BY #{ordering}" if ordering
        "          LEFT OUTER JOIN LATERAL (\n            SELECT  coalesce(jsonb_agg(jsonb_build_object('id', rel.\"\#{child_resource.primary_key_attr}\"::text,\n                                                          'type', '\#{child_resource.json_type}') \#{ordering}), '[]') AS j\n            FROM    \"\#{child_resource.table_name}\" rel\n            WHERE   rel.\"\#{child_resource.foreign_key}\" = \"\#{resource.table_name}\".\"\#{resource.primary_key}\"\n          ) \"rel_\#{child_resource.cte_name}\" ON true\n        EOQ\n      elsif not refl.reflection_sql.nil?  # can't use .present? since that loads the Relation!\n        case refl.reflection_sql\n        when String\n          raise \"TODO\"\n        when ActiveRecord::Relation\n          rel = refl.reflection_sql\n          sql = rel.select(<<~EOQ).to_sql\n            coalesce(jsonb_agg(jsonb_build_object('id', \"\#{child_resource.table_name}\".\"\#{child_resource.primary_key_attr}\"::text,\n                                                  'type', '\#{child_resource.json_type}')), '[]') AS j\n          EOQ\n          <<~EOQ\n            LEFT OUTER JOIN LATERAL (\n              \#{sql}\n            ) \"rel_\#{child_resource.cte_name}\" ON true\n          EOQ\n        end\n      end\n    elsif refl.has_one?\n      <<~EOQ\n        LEFT OUTER JOIN LATERAL (\n          SELECT  jsonb_build_object('id', rel.\"\#{child_resource.primary_key_attr}\"::text,\n                                    'type', '\#{child_resource.json_type}') AS j\n          FROM    \"\#{child_resource.table_name}\" rel\n          WHERE   rel.\"\#{child_resource.foreign_key}\" = \"\#{resource.table_name}\".\"\#{resource.primary_key}\"\n        ) \"rel_\#{child_resource.cte_name}\" ON true\n      EOQ\n    else\n      nil\n    end\n  }.compact.join(\"\\n\")\nend\n"

#json_key(name) ⇒ Object 



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# File 'lib/active_model_serializers/adapter/json_api_pg.rb', line 434

def json_key(name)
  JsonThing.json_key(name)
end

#many? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/active_model_serializers/adapter/json_api_pg.rb', line 430

def many?
  @many
end

#maybe_select_resource_relationships(resource) ⇒ Object 



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# File 'lib/active_model_serializers/adapter/json_api_pg.rb', line 708

def maybe_select_resource_relationships(resource)
  rels_sql = select_resource_relationships(resource)
  if rels_sql.nil?
    ''
  else
    %Q{, 'relationships', #{rels_sql}}
  end
end

#reflection_fields_for(resource) ⇒ Object 



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# File 'lib/active_model_serializers/adapter/json_api_pg.rb', line 787

def reflection_fields_for(resource)
  @reflection_fields_for[resource.full_name] ||= _reflection_fields_for(resource)
end

#select_resource(resource) ⇒ Object 



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# File 'lib/active_model_serializers/adapter/json_api_pg.rb', line 717

def select_resource(resource)
  fields = fields_for(resource)
  "    jsonb_build_object('id', \"\#{resource.table_name}\".\"\#{resource.primary_key_attr}\"::text,\n                       'type', '\#{resource.json_type}',\n                       'attributes', \#{select_resource_attributes(resource)}\n                       \#{maybe_select_resource_relationships(resource)})\n  EOQ\nend\n"

#select_resource_attribute(resource, field) ⇒ Object

Returns SQL for one JSON value for the resource’s ‘attributes’ object. If a field is an enum then we convert it from an int to a string. If a field has a #field__sql method on the ActiveRecord class, we use that instead.



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# File 'lib/active_model_serializers/adapter/json_api_pg.rb', line 451

def select_resource_attribute(resource, field)
  typ = resource.ar_class.attribute_types[field.to_s]
  if typ.is_a? ActiveRecord::Enum::EnumType
    "      CASE \#{typ.as_json['mapping'].map{|str, int| %Q{WHEN \"\#{resource.table_name}\".\"\#{field}\" = \#{int} THEN '\#{str}'}}.join(\"\\n     \")} END\n    EOQ\n  elsif resource.has_sql_method?(field)\n    resource.sql_method(field)\n  else\n    field = resource.unaliased(field)\n    # Standard AMS dasherizes json/jsonb/hstore columns,\n    # so we have to do the same:\n    if ActiveModelSerializers.config.key_transform == :dash\n      cl = resource.ar_class.attribute_types[field.to_s]\n      if column_is_jsonb? cl\n        %Q{jsonb_dasherize(\"\#{resource.table_name}\".\"\#{field}\")}\n      elsif column_is_jsonb_array? cl\n        # TODO: Could be faster:\n        # If we made the jsonb_dasherize function smarter so it could handle jsonb[],\n        # we wouldn't have to build a json object from the array then cast to jsonb[].\n        %Q{jsonb_dasherize(array_to_json(\"\#{resource.table_name}\".\"\#{field}\")::jsonb)}\n      elsif column_is_castable_to_jsonb? cl\n        # Fortunately we can cast hstore to jsonb,\n        # which gives us a solution that works whether or not the hstore extension is installed.\n        # Defining an hstore_dasherize function would work only if the extension were present.\n        %Q{jsonb_dasherize(\"\#{resource.table_name}\".\"\#{field}\"::jsonb)}\n      elsif column_is_castable_to_jsonb_array? cl\n        # TODO: Could be faster (see above):\n        %Q{jsonb_dasherize(array_to_json(\"\#{resource.table_name}\".\"\#{field}\"::jsonb[])::jsonb)}\n      else\n        %Q{\"\#{resource.table_name}\".\"\#{field}\"}\n      end\n    else\n      %Q{\"\#{resource.table_name}\".\"\#{field}\"}\n    end\n  end\nend\n"

#select_resource_attributes(resource) ⇒ Object

Given a JsonThing and the fields you want, outputs the json column for a SQL SELECT clause.



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# File 'lib/active_model_serializers/adapter/json_api_pg.rb', line 440

def select_resource_attributes(resource)
  fields = attribute_fields_for(resource)
  "    jsonb_build_object(\#{fields.map{|f| \"'\#{json_key(f)}', \#{select_resource_attribute(resource, f)}\"}.join(', ')})\n  EOQ\nend\n"

#select_resource_relationship(resource) ⇒ Object 



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# File 'lib/active_model_serializers/adapter/json_api_pg.rb', line 516

def select_resource_relationship(resource)
  if resource.belongs_to?
    fk = %Q{"#{resource.parent.table_name}"."#{resource.foreign_key}"}
    "      '\#{resource.json_key}',\n      jsonb_build_object('data',\n                         CASE WHEN \#{fk} IS NULL THEN NULL\n                              ELSE jsonb_build_object('id', \#{fk}::text,\n                                                      'type', '\#{resource.json_type}') END)\n    EOQ\n  elsif resource.has_many? or resource.has_one?\n    refl = resource.reflection\n    <<~EOQ\n      '\#{resource.json_key}',\n       jsonb_build_object(\#{refl.include_data ? %Q{'data', \"rel_\#{resource.cte_name}\".j} : ''}\n                          \#{refl.include_data && refl.links.any? ? ',' : ''}\n                          \#{refl.links.any? ? %Q{'links',  jsonb_build_object(\#{select_resource_relationship_links(resource, refl)})} : ''})\n    EOQ\n  else\n    raise \"Unknown kind of field reflection for \#{resource.full_name}\"\n  end\nend\n"

#select_resource_relationship_links(resource, reflection) ⇒ Object 



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# File 'lib/active_model_serializers/adapter/json_api_pg.rb', line 508

def select_resource_relationship_links(resource, reflection)
  reflection.links.map {|link_name, link_parts|
    "      '\#{link_name}', CONCAT(\#{link_parts.join(%Q{, \"\#{resource.parent.table_name}\".\"\#{resource.parent.primary_key_attr}\", })})\n    EOQ\n  }.join(\",\\n\")\nend\n"

#select_resource_relationships(resource) ⇒ Object 



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# File 'lib/active_model_serializers/adapter/json_api_pg.rb', line 539

def select_resource_relationships(resource)
  fields = reflection_fields_for(resource)
  children = fields.map{|f| get_json_thing(resource, f)}
  if children.any?
    "      jsonb_build_object(\#{children.map{|ch| select_resource_relationship(ch)}.join(', ')})\n    EOQ\n  else\n    nil\n  end\nend\n"

#serializer_attributes(resource) ⇒ Object

Returns all the attributes listed in the serializer, after checking include_foo? methods.



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# File 'lib/active_model_serializers/adapter/json_api_pg.rb', line 729

def serializer_attributes(resource)
  ms = Set.new(resource.serializer.instance_methods)
  resource.serializer._attributes.select{|f|
    if ms.include? "include_#{f}?".to_sym
      ser = resource.serializer.new(nil, @options)
      ser.send("include_#{f}?".to_sym)
    else
      true
    end
  }
end

#serializer_reflections(resource) ⇒ Object

Returns all the relationships listed in the serializer, after checking include_foo? methods.



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# File 'lib/active_model_serializers/adapter/json_api_pg.rb', line 743

def serializer_reflections(resource)
  ms = Set.new(resource.serializer.instance_methods)
  resource.serializer._reflections.keys.select{|f|
    if ms.include? "include_#{f}?".to_sym
      ser = resource.serializer.new(nil, @options)
      ser.send("include_#{f}?".to_sym)
    else
      true
    end
  }
end

#to_sql ⇒ Object 



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# File 'lib/active_model_serializers/adapter/json_api_pg.rb', line 796

def to_sql
  table_name = base_resource.table_name
  maybe_included = if include_selects.any?
                     %Q{, 'included', inc.j}
                   else
                     ''
                   end
  return "  WITH\n  t AS (\n    \#{base_relation.select(%Q{\"\#{base_resource.table_name}\".*}).to_sql}\n  ),\n  t2 AS (\n    \#{many? ? \"SELECT  COALESCE(jsonb_agg(\#{select_resource(base_resource)}), '[]') AS j\"\n            : \"SELECT                     \#{select_resource(base_resource)}         AS j\"}\n    FROM    t AS \"\#{base_resource.table_name}\"\n    \#{join_resource_relationships(base_resource)}\n  ),\n  \#{include_ctes}\n  \#{include_jbsses}\n  all_jbsses AS (\n    SELECT  '{}'::jsonb AS j\n    WHERE   1=0\n    \#{include_selects.join(\"\\n\")}\n  ),\n  inc AS (\n    SELECT  COALESCE(jsonb_agg(j), '[]') AS j\n    FROM    all_jbsses\n  )\nSELECT jsonb_build_object('data', t2.j\n                             \#{maybe_included})\n  FROM    t2\n  CROSS JOIN  inc\n"
end