IEEE 1636.2:2010 pdf free download – Exchanging Maintenance Action Information via the Extensible Markup Language (XML)
4.1 General
The MAl schema formally defines the structure (model) and constraints for expressing MAI XMLdocuments. This schema defines rules that can be used for document generation and data validation, and isan essential requirement to ensure the effective use of data in an open system environment and aids in thereuse and interoperability of maintenance data elements derived from this schema.
This schema is arranged in a hierarchical (element) approach,which consists of simple and complex datatypes.The structure was created to help illustrate the intended semantic interpretation of the data based onthe conceptual relationships of maintenance action elements.
All elements in this document with a base type from SimicaCommon.”sc:” identifies that type or attributegroup that can be found in Annex B.
All elements in this document with a base type from Common“c:” identifies that type or attribute groupthat can be found in IEEE Std 1671-2006,Annex B.These entities are not listed within this document.
Elements are defined through the description of their attributes and child elements. Where an element hashierarchy, the element and its associated child elements are shown in a figure in Clause 4.The Clause 4figures show a hierarchal layout of the schema structure and illustrate the XML types (both simple andcomplex) that comprise the element. Within the Clause 4 figures, the “solid lined boxes”indicate that thexML type shall be required, while “dotted lined boxes” indicate that the XML type may be used (optional).where the child element has hierarchy, details of the child elements will follow in the appropriate clauses.
5.Conformance
The minimal expectations for MAI-conformant XML instance documents shall be that the instancedocument is considered valid if said document complies with the constraints expressed in the MAl andSIMICA Common schemas and information models (see Annex A and Annex C).
6. Extensibility
The provision of an extension mechanism is necessary to ensure the viability of the specification and allowproducers and consumers of SIMICA 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.
MAl schemas support two forms of extension, as follows:
a)Wildcard-based extensions allow for the extension of SIMICA schemas with additional clements.b)Type derivation allows for extending the set of data types by deriving a new type from an existing type.
b)XML schemas control the location and type of extension allowed.
An element has an extensible content model if in instance documents that element can contain elements anddata beyond that specified by the schema. SIMICA schemas should explicitly identify where they can beextended.Only elements from a namespace different from the document namespace should be allowed inan extension.The schema shall use the SimicaCommon <Extension> type to identify where extension isallowed.
Allowing the extension of a schema using type substitution should be avoided. Schemas should markelements defined via a simple or complex type with the block attribute set to #all if type substitution is tobe avoided.Elements that use type substitution as their means of definition should set the abstract attributeto true.