1、raising standards worldwide NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW BSI Standards Publication BS ISO/IEC 20944-2:2013 Information technology Metadata Registries Interoperability and Bindings (MDR-IB) Part 2: Coding bindingsBS ISO/IEC 20944-2:2013 BRITISH STANDARD Natio
2、nal foreword This British Standard is the UK implementation of ISO/IEC 20944-2:2013. The UK participation in its preparation was entrusted to T e c h n i c a l C o m m i t t e e I S T / 4 0 , D a t a m a n a g e m e n t a n d i n t e r c h a n g e . A list of organizations represented on this commit
3、tee can be obtained on request to its secretary. This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. The British Standards Institution 2013. Published by BSI Standards Limited 2013. ISBN 978 0 580 53626 7 ICS 35.
4、040 Compliance with a British Standard cannot confer immunity from legal obligations. This British Standard was published under the authority of the Standards Policy and Strategy Committee on 31 January 2013. Amendments issued since publication Date T e x t a f f e c t e dBS ISO/IEC 20944-2:2013Refe
5、rence number ISO/IEC 20944-2:2013(E) ISO/IEC 2013INTERNATIONAL STANDARD ISO/IEC 20944-2 First edition 2013-01-15 Information technology Metadata Registries Interoperability and Bindings (MDR-IB) Part 2: Coding bindings Technologies de linformation Interoprabilit et liaisons des registres de mtadonne
6、s (MDR-IB) Partie 2: Liaisons de codage BS ISO/IEC 20944-2:2013 ISO/IEC 20944-2:2013(E) COPYRIGHT PROTECTED DOCUMENT ISO/IEC 2013 All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, includin
7、g photocopying and microfilm, without permission in writing from either ISO at the address below or ISOs member body in the country of the requester. ISO copyright office Case postale 56 CH-1211 Geneva 20 Tel. + 41 22 749 01 11 Fax + 41 22 749 09 47 E-mail copyrightiso.org Web www.iso.org Published
8、in Switzerland ii ISO/IEC 2013 All rights reservedBS ISO/IEC 20944-2:2013 ISO/IEC 20944-2:2013(E) ISO/IEC 2013 All rights reserved iiiContents Page Foreword iv Introduction . v 1 Scope 1 2 Normative references 1 3 Terms and definitions . 1 4 Intended use of this part of ISO/IEC 20944 . 1 5 Abstract
9、model 2 5.1 Overview of data objects 2 5.2 Referenced data interchange specification 2 5.3 Data structuring model . 3 5.4 Designations, identifiers, and navigation . 4 6 Semantics . 6 6.1 Datatypes . 6 6.2 Inherent structure 6 6.3 Hierarchical naming 6 6.4 Associated properties . 7 6.5 Merged naviga
10、tion identifiers for properties 8 6.6 External, logical, and internal naming conventions 8 6.7 The _value property 9 6.8 Keywords . 9 7 Bindings . 9 8 Administration . 9 8.1 Use of registry-defined datatypes . 9 9 Conformance . 10 9.1 Coding conformance paradigm . 10 9.2 Data instance conformance .
11、10 9.3 Data application conformance . 10 9.4 Conformance labels 12 10 Reserved for future standardization 12 11 Dotted Identifier Value Pair (DIVP) coding binding 12 11.1 General . 12 11.2 Generating and producing DIVP 14 11.3 Consuming and interpreting DIVP . 16 11.4 Representation of basic data ty
12、pes . 17 11.5 Encoding of character representations 19 11.6 Handling exceptions and extensions 19 11.7 Conformance label prefix . 20 12 XML coding binding 20 12.1 General . 20 12.2 Generating and producing XML . 20 12.3 Consuming and interpreting XML 23 12.4 Representation of basic data types . 24 1
13、2.5 Encoding of character representations 27 12.6 Handling exceptions and extensions 27 12.7 Conformance label prefix . 27 Bibliography 28 BS ISO/IEC 20944-2:2013 ISO/IEC 20944-2:2013(E) iv ISO/IEC 2013 All rights reservedForeword ISO (the International Organization for Standardization) and IEC (the
14、 International Electrotechnical Commission) form the specialized system for worldwide standardization. National bodies that are members of ISO or IEC participate in the development of International Standards through technical committees established by the respective organization to deal with particu
15、lar fields of technical activity. ISO and IEC technical committees collaborate in fields of mutual interest. Other international organizations, governmental and non-governmental, in liaison with ISO and IEC, also take part in the work. In the field of information technology, ISO and IEC have establi
16、shed a joint technical committee, ISO/IEC JTC 1. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of the joint technical committee is to prepare International Standards. Draft International Standards adopted by the joint technica
17、l committee are circulated to national bodies for voting. Publication as an International Standard requires approval by at least 75 % of the national bodies casting a vote. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO and I
18、EC shall not be held responsible for identifying any or all such patent rights. ISO/IEC 20944-2 was prepared by Joint Technical Committee ISO/IEC JTC 1, Information technology, Subcommittee SC 32, Data management and interchange. ISO/IEC 20944 consists of the following parts, under the general title
19、 Information technology Metadata Registries Interoperability and Bindings (MDR-IB): Part 1: Framework, common vocabulary, and common provisions for conformance Part 2: Coding bindings Part 3: API bindings Part 4: Protocol bindings Part 5: Profiles BS ISO/IEC 20944-2:2013 ISO/IEC 20944-2:2013(E) ISO/
20、IEC 2013 All rights reserved vIntroduction The ISO/IEC 20944 series of International Standards provides the bindings and their interoperability for metadata registries, such as those specified in the ISO/IEC 11179 series of International Standards. This part of ISO/IEC 20944 contains provisions that
21、 are common to coding bindings (Clauses 4-10) and the coding bindings themselves (Clause 11 onward). The coding bindings have commonality in their conceptualization of data instances and their internal structures. For example, common features include: using datatypes to characterize the nature and o
22、perations upon data; using ISO/IEC 11404 to define and declare datatypes; using common aggregate structures, such as array and record, to describe sets of data; using common navigation descriptions to reference components within a set of data. The individual coding bindings each incorporate a mappin
23、g of common data semantics to their individual binding requirements. BS ISO/IEC 20944-2:2013BS ISO/IEC 20944-2:2013 INTERNATIONAL STANDARD ISO/IEC 20944-2:2013(E) ISO/IEC 2013 All rights reserved 1Information technology Metadata Registries Interoperability and Bindings (MDR-IB) Part 2: Coding bindin
24、gs 1 Scope The ISO/IEC 20944 series of International Standards describes codings, application programming interfaces (APIs), and protocols for interacting with an ISO/IEC 11179 metadata registry (MDR). This part of ISO/IEC 20944 specifies provisions that are common across coding bindings for the ISO
25、/IEC 20944 series. This part of ISO/IEC 20944 includes the individual coding bindings themselves. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest
26、 edition of the referenced document (including any amendments) applies. ISO/IEC 11404:2007, Information technology General-Purpose Datatypes (GPD) ISO/IEC 20944-1:2013, Information technology Metadata Registries Interoperability and Bindings (MDR-IB) Framework, common vocabulary, and common provisio
27、ns for conformance 3 Terms and definitions For the purposes of this document, the terms and definitions given in ISO/IEC 20944-1 apply. 4 Intended use of this part of ISO/IEC 20944 Bindings concern the mapping of one standard (or framework) into another standard (or framework). 1Coding bindings conc
28、ern the mapping of instances of data models to code elements (representations of data). More than one standard (or framework) may be used to complete the mapping. 2The ISO/IEC 20944 series of International Standards uses at least three tiers of mappings. The first tier concerns the main kind of mapp
29、ing for the binding: coding bindings, API bindings, and protocol bindings. The 1For example, an ASN.1 binding of “technical specification XYZ“ implies mapping the features and requirements of “technical specification XYZ“ to the features and capabilities of the ASN.1 standard. 2When viewed as a seri
30、es of layers (e.g., data model = Standard XYZ, coding binding = ASN.1, encoding = ASN.1 Basic Encoding Rules (BER), bindings may also be viewed as “layered standards“ or a “layering of standards“. BS ISO/IEC 20944-2:2013 ISO/IEC 20944-2:2013(E) 2 ISO/IEC 2013 All rights reservedsecond tier of mappin
31、g concerns the mapping of data model instances to a coding-independent representation (CIR) of data ISO/IEC 11404 specifies the syntax and semantics of this CIR. The third tier of mapping concerns the mapping of CIR to a coding-specific representation (CSR) Clauses 11 and onward describe the coding-
32、specific mappings. Additional tiers of mapping are possible, such as specifications of encoding mappings. 3The purpose of a common CIR of data is to support common semantics and interoperability among coding bindings and other bindings, such as API and protocol bindings. NOTE XML bindings are useful
33、 for integration with other XML technologies. The XML binding provides the requirements of XML interchange without specifying the XML technologies (e.g., XML Schema) to implement the features. DIVP bindings are useful for integration with name-value pair technologies, such as scripting systems, E-ma
34、il, and web servers. EXAMPLE A CIR is developed for a data model. Based upon this CIR, it is possible to transform one coding binding (e.g., XML coding binding) to another coding binding (e.g., ASN.1 coding binding) while sharing common semantics (the CIR) among the coding bindings. Likewise, one co
35、ding-specific representation (e.g., XML) can be transformed into another coding-specific representation (e.g., ASN.1). 5 Abstract model The coding bindings have commonality in their conceptualization of data instances and their internal structures. For example, common features include: using datatyp
36、es to characterize the nature and operations upon data using ISO/IEC 11404 to define and declare datatypes using common aggregate structures, such as array and record, to describe sets of data using common navigation descriptions to reference components within a set of data The individual coding bin
37、dings (Clauses 11 and onward) each incorporate a mapping of common data semantics to their individual binding requirements. 5.1 Overview of data objects The conceptual model of data objects is divided into two parts: the data structuring model and the navigation model. The data structuring model des
38、cribes the “logical“ structure of data as it is transferred. The navigation model describes the mapping of the logical structure to a navigation hierarchy. NOTE The use of hierarchical naming does not imply a hierarchical data model or metadata model. 5.2 Referenced data interchange specification Th
39、e ISO/IEC 20944 series of International Standards is organized by an implicit data interchange specification. This data interchange specification is external to the coding, API, and protocol bindings. (See footnote 2.) 3The XML, ASN.1, and DIVP coding bindings all have additional tiers for encoding.
40、 XML has two additional encoding tiers: character encoding (e.g., ASCII vs. UTF-8), and a lower level byte-ordering encoding for multi-octet representations (e.g., little endian and big endian orderings for UTF-16 and UTF-32). ASN.1 has an additional layer of encoding, Encoding Rules (BER), Canonica
41、l Encoding Rules (CER), and Distinguished Encoding Rules (DER). DIVP may have encoding rules specified by its outer wrapper, but they are not part of the DIVP coding binding. BS ISO/IEC 20944-2:2013 ISO/IEC 20944-2:2013(E) ISO/IEC 2013 All rights reserved 35.3 Data structuring model 5.3.1 Data objec
42、ts 5.3.1.1 General A unit or collection of data is called a “data object“. 4Data objects are structured data characterized by the following. 5.3.1.2 Atomic data objects An object may be an “atomic data object“ if the data object has values which are intrinsically indivisible, e.g., a basic type such
43、 as integer, real, character. EXAMPLE 17, -1.7E8, 0D19980831235959, “hello world“. 5.3.1.3 Aggregates An aggregate is a collection of data objects (atomic or not). Each member of the aggregate is called a “component“. The components may be ordered or unordered, named or unnamed, typed or untyped. An
44、 aggregate may be nested, i.e., a component of aggregate may be an aggregate itself. EXAMPLE The list X: 17 Y: 18 19 20 Z: 0D19980831232359 contains three named data elements X, Y, and Z. The first component (X) is an atomic data object of type integer. he second component (Y) is an aggregate of thr
45、ee unnamed component. The third component (Z) is an atomic data object of type date-and-time. The difference between an aggregate and a C programming language structure is: a C structure is always ordered, named, and typed; whereas an aggregate may be ordered, named, and/or typed. 5.3.1.4 Hierarchic
46、al organization The nesting implies a hierarchical organization only from the perspective of data access, not from data implementation. For example, a multi-dimensional array may use the same access method as a nested list. As an analogy, when comparing the C programming language two-dimensional arr
47、ay char x1020 to the nested list char *y10, both types are accessed by the same hierarchical method: xab and yab. 5.3.1.5 Datatypes Data objects may have a datatype. ISO/IEC 11404 includes basic types (e.g., boolean, integer, real, date-time, string), type parameters (e.g., precision), and type oper
48、ators (e.g., lists, records, sets). Implementations shall support the ISO/IEC 11404 datatypes 5 . Additional supported datatypes are implementation-defined. 5.3.2 Properties 5.3.2.1 General Properties can be associated with data objects. Properties are attributes of the data object. 5.3.2.2 Property
49、 lists Each data object may have an associated property list. A property list is an ordered, named list of data objects. EXAMPLE The data object 1 2 3 might have the property list read_write_access: read_only size: 123 . 4Not to be confused with “objects“ of “object-oriented“ analysis, design, and programming. 5ISO/IEC 11404 includes a description of datatype conformity. BS ISO/IEC 20944-2:2013 ISO/IEC 20944-2:2013(E) 4 ISO/IEC 2013 All rights reserved5.3.2.3 System
