Support different column names for MySQL and Postgres

lib/database_cleaner/active_record/base.rb

@@ -65,10 +65,10 @@ module DatabaseCleaner
         end
       end
 
-      def self.exclusion_condition
+      def self.exclusion_condition(column_name)
-        result = " table_name <> '#{::DatabaseCleaner::ActiveRecord::Base.migration_table_name}' "
+        result = " #{column_name} <> '#{::DatabaseCleaner::ActiveRecord::Base.migration_table_name}' "
         if ::ActiveRecord::VERSION::MAJOR >= 5
-          result += " AND table_name <> '#{ActiveRecord::Base.internal_metadata_table_name}' "
+          result += " AND #{column_name} <> '#{ActiveRecord::Base.internal_metadata_table_name}' "
         end
         result
       end

lib/database_cleaner/active_record/deletion.rb

@@ -72,7 +72,7 @@ module DatabaseCleaner::ActiveRecord
                INFORMATION_SCHEMA.TABLES
                WHERE
                table_schema = '#{db_name}'
-               AND #{::DatabaseCleaner::ActiveRecord::Base.exclusion_condition};
+               AND #{::DatabaseCleaner::ActiveRecord::Base.exclusion_condition('table_name')};
         SQL
       end
     end

lib/database_cleaner/active_record/truncation.rb

@@ -192,7 +192,7 @@ module DatabaseCleaner
           FROM pg_tables
           WHERE
             tablename !~ '_prt_' AND
-            #{::DatabaseCleaner::ActiveRecord::Base.exclusion_condition} AND
+            #{::DatabaseCleaner::ActiveRecord::Base.exclusion_condition('tablename')} AND
             schemaname = ANY (current_schemas(false))
         _SQL
         rows.collect { |result| result.first }