IEEE 1671.6:2008 pdf free download – IEEE Trial-Use Standard for Automatic Test Markup Language(ATML) for Exchanging Automatic Test Information via XML: Exchanging Test Station Information
5.5 Inherited simple types
Within the W3C XML schema hierarchy, all types derive from the root type anyType. The first branchwithin this hierarchy is comprised of two groups: simple types and complex types. A simple type providesa name unique within a schema for one of the base XML datatypes and may not have child elements.Optionally, constraints may be imposed to limit the content of elements derived from the simple type.
Any utilized simple type not specifically defined within the TestStationInstance schema shall be inheritedfrom the imported schemas Common.xsd and HardwareCommon.xsd defined in Annex B of IEEE Std 1671-2006.
5.6 Inherited complex types
The second major branch of the W3C XML schema hierarchy is the“complex type.”An XML complextype may derive from one of the W3C XML base types or from a schema-defined simple type.Unlike asimple type, a complex type may have subordinate child elements along with restrictions or extensions ofthe inherited base type. The hierarchical nature of XML schema likewise permits the child elements of acomplex type to also be complex types.
Any utilized complex type not specifically defined within the TestStationInstance schema shall be inheritedfrom the imported schemas Common.xsd，HardwareCommon.xsd and TestEquipment.xsd defined inAnnex B of IEEE Std 1671-2006.
5.7 Inherited attribute groups
Any utilized attribute groups not specifically defined within the TestStationDescription schema shall beinherited from the imported schemas Common.xsd and HardwareCommon.xsd defined in Annex B ofIEEE Std 1671-2006.
6.Conformance
The minimal expectations for TestStationDescription conformant XML instance documents shall be thatthe instance document is considered valid if said document complies with the constraints expressed in theTestStationDescription schema associated with this trial-use standard as well as any constraints imposed byinherited elements from Annex B of IEEE Std 1671-2006,when said instance document is completelypopulated.
The minimal expectations for TestStationInstance conformant XML instance documents shall be that theinstance document is considered valid if said document complies with the constraints expressed in theTestStationInstance schema associated with this trial-use standard as well as any constraints imposed byinherited elements from Annex B of IEEE Std 1671-2006,when said instance document is completelypopulated.
Extensions are permitted to both the TestStationDescription and TestStationInstance schemas, but shallonly occur through the facility of the extensibility mechanism described in Clause 7. In short, extensionsmay only appear in the specific <extension> tags provided in the associated XML schema. As defined inthe w3C XML schema standard [B1], an extended schema must conform to the W3C XML schemaspecification and shall not contain any entities defined in the base schema.
7.Extensibility
The provision of an extension mechanism is necessary to ensure the viability of the specification and allowproducers and consumers of ATML instance documents to interoperate in those cases where there is arequirement to exchange relevant data that is not included in the trial-use standard XML schema. The useof the extensions shall be done in a way that ensures that a conformant consumer can utilize the extendedfile without error, discard or otherwise sidestep the extended data and use the non-extended portions of thedata as it is intended— -without error or loss of functionality.
Extensions shall be additional information added to the content model of the element being extended.
Extensions shall not repackage existing information entities that are already supported by the trial-usestandard.
An extended instance document shall be accompanied by the extension XML schema and documentationsufficient to explain the need for the extension as well as the underlying semantics and relationship(s) to thebase schema.
TestStationDescription and TestStationInstance schemas support two forms of extension:
a)Wildcard-based cxtensions allow for thc extension of ATML schemas with additional clements.
b)Type derivation allows for extending the set of data types by deriving a new type from an existing type.