# File lib/AWS/RDS/rds.rb, line 353
353:       def modify_db_instance( options = {})
354:         raise ArgumentError, "No :db_instance_identifier provided" if options.does_not_have?(:db_instance_identifier)
355: 
356:         # handle a former argument that was misspelled
357:         raise ArgumentError, "Perhaps you meant :backup_retention_period" if options.has?(:backend_retention_period)
358: 
359:         params = {}
360:         params['DBInstanceIdentifier'] = options[:db_instance_identifier]
361: 
362:         params["AllocatedStorage"] = options[:allocated_storage].to_s if options.has?(:allocated_storage)
363:         params["DBInstanceClass"] = options[:db_instance_class] if options.has?(:db_instance_class)
364:         params["Engine"] = options[:engine] if options.has?(:engine)
365:         params["MasterUsername"] = options[:master_username] if options.has?(:master_username)
366:         params["MasterUserPassword"] = options[:master_user_password] if options.has?(:master_user_password)
367:         params["Port"] = options[:port].to_s if options.has?(:port)
368:         params["DBName"] = options[:db_name] if options.has?(:db_name)
369:         params["DBParameterGroupName"] = options[:db_parameter_group_name] if options.has?(:db_parameter_group_name)
370:         params["DBSecurityGroups"] = options[:db_security_groups] if options.has?(:db_security_groups)
371:         params["AvailabilityZone"] = options[:availability_zone] if options.has?(:availability_zone)
372:         params["PreferredMaintenanceWindow"] = options[:preferred_maintenance_window] if options.has?(:preferred_maintenance_window)
373:         params["BackupRetentionPeriod"] = options[:backup_retention_period].to_s if options.has?(:backup_retention_period)
374:         params["PreferredBackupWindow"] = options[:preferred_backup_window] if options.has?(:preferred_backup_window)
375: 
376:         return response_generator(:action => "ModifyDBInstance", :params => params)
377:       end