diff --git a/activerecord/lib/active_record/fixture_set/table_row.rb b/activerecord/lib/active_record/fixture_set/table_row.rb
new file mode 100644
index 0000000000..5f72c1df38
--- /dev/null
+++ b/activerecord/lib/active_record/fixture_set/table_row.rb
@@ -0,0 +1,79 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  class FixtureSet
+    class TableRow # :nodoc:
+      def initialize(fixture, table_rows:, label:, now:)
+        @table_rows = table_rows
+        @label = label
+        @now = now
+        @row = fixture.to_hash
+        fill_row_model_attributes
+      end
+
+      def to_hash
+        @row
+      end
+
+      private
+
+        def model_metadata
+          @table_rows.model_metadata
+        end
+
+        def model_class
+          @table_rows.model_class
+        end
+
+        def fill_row_model_attributes
+          return unless model_class
+          fill_timestamps
+          interpolate_label
+          generate_primary_key
+          resolve_enums
+          @table_rows.resolve_sti_reflections(@row)
+        end
+
+        def reflection_class
+          @reflection_class ||= if @row.include?(model_metadata.inheritance_column_name)
+            @row[model_metadata.inheritance_column_name].constantize rescue model_class
+          else
+            model_class
+          end
+        end
+
+        def fill_timestamps
+          # fill in timestamp columns if they aren't specified and the model is set to record_timestamps
+          if model_class.record_timestamps
+            model_metadata.timestamp_column_names.each do |c_name|
+              @row[c_name] = @now unless @row.key?(c_name)
+            end
+          end
+        end
+
+        def interpolate_label
+          # interpolate the fixture label
+          @row.each do |key, value|
+            @row[key] = value.gsub("$LABEL", @label.to_s) if value.is_a?(String)
+          end
+        end
+
+        def generate_primary_key
+          # generate a primary key if necessary
+          if model_metadata.has_primary_key_column? && !@row.include?(model_metadata.primary_key_name)
+            @row[model_metadata.primary_key_name] = ActiveRecord::FixtureSet.identify(
+              @label, model_metadata.primary_key_type
+            )
+          end
+        end
+
+        def resolve_enums
+          model_class.defined_enums.each do |name, values|
+            if @row.include?(name)
+              @row[name] = values.fetch(@row[name], @row[name])
+            end
+          end
+        end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/fixture_set/table_rows.rb b/activerecord/lib/active_record/fixture_set/table_rows.rb
new file mode 100644
index 0000000000..c7227ef133
--- /dev/null
+++ b/activerecord/lib/active_record/fixture_set/table_rows.rb
@@ -0,0 +1,97 @@
+# frozen_string_literal: true
+
+require "active_record/fixture_set/table_row"
+require "active_record/fixture_set/model_metadata"
+
+module ActiveRecord
+  class FixtureSet
+    class TableRows # :nodoc:
+      def initialize(table_name, model_class:, fixtures:, config:)
+        @table_name  = table_name
+        @model_class = model_class
+
+        # track any join tables we need to insert later
+        @tables = Hash.new { |h, table| h[table] = [] }
+
+        build_table_rows_from(fixtures, config)
+      end
+
+      attr_reader :table_name, :model_class
+
+      def to_hash
+        @tables.transform_values { |rows| rows.map(&:to_hash) }
+      end
+
+      def model_metadata
+        @model_metadata ||= ModelMetadata.new(model_class, table_name)
+      end
+
+      def resolve_sti_reflections(row)
+        # If STI is used, find the correct subclass for association reflection
+        reflection_class = reflection_class_for(row)
+
+        reflection_class._reflections.each_value do |association|
+          case association.macro
+          when :belongs_to
+            # Do not replace association name with association foreign key if they are named the same
+            fk_name = (association.options[:foreign_key] || "#{association.name}_id").to_s
+
+            if association.name.to_s != fk_name && value = row.delete(association.name.to_s)
+              if association.polymorphic? && value.sub!(/\s*\(([^\)]*)\)\s*$/, "")
+                # support polymorphic belongs_to as "label (Type)"
+                row[association.foreign_type] = $1
+              end
+
+              fk_type = reflection_class.type_for_attribute(fk_name).type
+              row[fk_name] = ActiveRecord::FixtureSet.identify(value, fk_type)
+            end
+          when :has_many
+            if association.options[:through]
+              add_join_records(row, HasManyThroughProxy.new(association))
+            end
+          end
+        end
+      end
+
+      private
+
+        def build_table_rows_from(fixtures, config)
+          now = config.default_timezone == :utc ? Time.now.utc : Time.now
+
+          @tables[table_name] = fixtures.map do |label, fixture|
+            TableRow.new(
+              fixture,
+              table_rows: self,
+              label: label,
+              now: now,
+            )
+          end
+        end
+
+        def reflection_class_for(row)
+          if row.include?(model_metadata.inheritance_column_name)
+            row[model_metadata.inheritance_column_name].constantize rescue model_class
+          else
+            model_class
+          end
+        end
+
+        def add_join_records(row, association)
+          # This is the case when the join table has no fixtures file
+          if (targets = row.delete(association.name.to_s))
+            table_name  = association.join_table
+            column_type = association.primary_key_type
+            lhs_key     = association.lhs_key
+            rhs_key     = association.rhs_key
+
+            targets = targets.is_a?(Array) ? targets : targets.split(/\s*,\s*/)
+            joins   = targets.map do |target|
+              { lhs_key => row[model_metadata.primary_key_name],
+                rhs_key => ActiveRecord::FixtureSet.identify(target, column_type) }
+            end
+            @tables[table_name].concat(joins)
+          end
+        end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/fixtures.rb b/activerecord/lib/active_record/fixtures.rb
index 30fbc2a84a..9c05843999 100644
--- a/activerecord/lib/active_record/fixtures.rb
+++ b/activerecord/lib/active_record/fixtures.rb
@@ -8,7 +8,7 @@ require "active_support/dependencies"
 require "active_support/core_ext/digest/uuid"
 require "active_record/fixture_set/file"
 require "active_record/fixture_set/render_context"
-require "active_record/fixture_set/model_metadata"
+require "active_record/fixture_set/table_rows"
 require "active_record/test_fixtures"
 require "active_record/errors"
 
@@ -656,76 +656,15 @@ module ActiveRecord
     # Returns a hash of rows to be inserted. The key is the table, the value is
     # a list of rows to insert to that table.
     def table_rows
-      now = config.default_timezone == :utc ? Time.now.utc : Time.now
-
       # allow a standard key to be used for doing defaults in YAML
       fixtures.delete("DEFAULTS")
 
-      # track any join tables we need to insert later
-      rows = Hash.new { |h, table| h[table] = [] }
-
-      rows[table_name] = fixtures.map do |label, fixture|
-        row = fixture.to_hash
-
-        if model_class
-          # fill in timestamp columns if they aren't specified and the model is set to record_timestamps
-          if model_class.record_timestamps
-            model_metadata.timestamp_column_names.each do |c_name|
-              row[c_name] = now unless row.key?(c_name)
-            end
-          end
-
-          # interpolate the fixture label
-          row.each do |key, value|
-            row[key] = value.gsub("$LABEL", label.to_s) if value.is_a?(String)
-          end
-
-          # generate a primary key if necessary
-          if model_metadata.has_primary_key_column? && !row.include?(model_metadata.primary_key_name)
-            row[model_metadata.primary_key_name] = ActiveRecord::FixtureSet.identify(label, model_metadata.primary_key_type)
-          end
-
-          # Resolve enums
-          model_class.defined_enums.each do |name, values|
-            if row.include?(name)
-              row[name] = values.fetch(row[name], row[name])
-            end
-          end
-
-          # If STI is used, find the correct subclass for association reflection
-          reflection_class =
-            if row.include?(model_metadata.inheritance_column_name)
-              row[model_metadata.inheritance_column_name].constantize rescue model_class
-            else
-              model_class
-            end
-
-          reflection_class._reflections.each_value do |association|
-            case association.macro
-            when :belongs_to
-              # Do not replace association name with association foreign key if they are named the same
-              fk_name = (association.options[:foreign_key] || "#{association.name}_id").to_s
-
-              if association.name.to_s != fk_name && value = row.delete(association.name.to_s)
-                if association.polymorphic? && value.sub!(/\s*\(([^\)]*)\)\s*$/, "")
-                  # support polymorphic belongs_to as "label (Type)"
-                  row[association.foreign_type] = $1
-                end
-
-                fk_type = reflection_class.type_for_attribute(fk_name).type
-                row[fk_name] = ActiveRecord::FixtureSet.identify(value, fk_type)
-              end
-            when :has_many
-              if association.options[:through]
-                add_join_records(rows, row, HasManyThroughProxy.new(association))
-              end
-            end
-          end
-        end
-
-        row
-      end
-      rows
+      TableRows.new(
+        table_name,
+        model_class: model_class,
+        fixtures: fixtures,
+        config: config,
+      ).to_hash
     end
 
     class ReflectionProxy # :nodoc:
@@ -762,26 +701,6 @@ module ActiveRecord
 
     private
 
-      def add_join_records(rows, row, association)
-        # This is the case when the join table has no fixtures file
-        if (targets = row.delete(association.name.to_s))
-          table_name  = association.join_table
-          column_type = association.primary_key_type
-          lhs_key     = association.lhs_key
-          rhs_key     = association.rhs_key
-
-          targets = targets.is_a?(Array) ? targets : targets.split(/\s*,\s*/)
-          rows[table_name].concat targets.map { |target|
-            { lhs_key => row[model_metadata.primary_key_name],
-              rhs_key => ActiveRecord::FixtureSet.identify(target, column_type) }
-          }
-        end
-      end
-
-      def model_metadata
-        @model_metadata ||= ModelMetadata.new(model_class, table_name)
-      end
-
       def model_class=(class_name)
         if class_name.is_a?(Class) # TODO: Should be an AR::Base type class, or any?
           @model_class = class_name