1 files changed, 6 insertions, 2 deletions
diff --git a/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb b/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb
index 61bac6741f..1ce5f5ae58 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb
@@ -63,7 +63,7 @@ module ActiveRecord
 
       def column_spec_for_primary_key(column)
         spec = {}
-        if column.extra == 'auto_increment'
+        if column.auto_increment?
           return unless column.limit == 8
           spec[:id] = ':bigint'
         else
@@ -103,6 +103,10 @@ module ActiveRecord
           collation && !collation.match(/_ci$/)
         end
 
+        def auto_increment?
+          extra == 'auto_increment'
+        end
+
         private
 
         # MySQL misreports NOT NULL column default when none is given.
@@ -808,7 +812,7 @@ module ActiveRecord
         options = {
           default: column.default,
           null: column.null,
-          auto_increment: column.extra == "auto_increment"
+          auto_increment: column.auto_increment?
         }
 
         current_type = select_one("SHOW COLUMNS FROM #{quote_table_name(table_name)} LIKE '#{column_name}'", 'SCHEMA')["Type"]