# File lib/data_mapper/constraints/adapters/do_adapter.rb, line 17
        def constraint_exists?(storage_name, constraint_name)
          statement = DataMapper::Ext::String.compress_lines("SELECT COUNT(*)\nFROM \#{quote_name('information_schema')}.\#{quote_name('table_constraints')}\nWHERE \#{quote_name('constraint_type')} = 'FOREIGN KEY'\nAND \#{quote_name('table_schema')} = ?\nAND \#{quote_name('table_name')} = ?\nAND \#{quote_name('constraint_name')} = ?\n")

          select(statement, schema_name, storage_name, constraint_name).first > 0
        end