Simple types specify the constraints and information about the values of attributes or text-only elements. Simple types do not contain children.
The following example shows the OriginDestinationInformation element (blue) from the OTA Low Fare Search request. This element contains the RPH attribute (green) defined by RPH_Type, which is a simple type. RPH_Type can provide the constraints on what you can enter for the RPH attribute.
To see the relationship between the element, simple type, and attribute, click OriginDestinationInformation.