1、I N T E R N AT I O NA L STANDARD ISO/IEC 821 I Second edition 1994-1 0-01 Information technology - Specification for a data descriptive file for information interchange Technologies de linformation - Spcifications pour fichier de donnes descriptif pour lchange dinformation Reference number ISO/IEC 8
2、21 1 :1994(E) = 4851903 0580344 Lb9 = ISOAEC 821 1 : 1994(E) Con tents I 2 Normative references . I 3 Conformance . 2 2 4.1 Definitions 4.2 Abbreviations 5 . 6 5.1 File and logical record structure . 7 5.1.1 Interchange logical records . . 7 5.2.1 Logical record leade 5.2.1.1 record length fi 5.2.1.
3、3 ISO/IEC 821 1 version number (LR RP 8) . 8 5.2.1.5 Entry map field (LR RP 20-23) . 5.2.1.2 leader identifier field (LR RP 6) 8 5.2.1.4 Base address of field area (LR RP 12-16) 8 9 5.2.1.5.2 Size of field position field (LR RP 21 5.2.1.5.3 Reserved for future standardization 5.2.1.5.4 Size of field
4、 tag field (LR RP 23) . 5.2.1.6 Alternate forms of counts and field positions . 5.2.2 Logical record direct 5.2.2.1 Field tag field 5.3.2.1 User data fields 5.3.2.1. I Elementary data fields Il 5.3.2.1.2 Compound data 6 Description of user data types and stru 6.1 DDR leader fields related to data 6.
5、1.1 Interchange level field (DDR 6.1.2 Inline code extension indicator (DDR RP 7) 12 6.1.3 Application indicator field (DDR RP 9) 12 6.1.4 Field control length field (DDR RP 1 . 6.1.3.1 Reference to other standards 12 12 6.1.5 Extended character set indicator fiel 12 6.2.1 File control field (tag =
6、O.O) 12 13 . 13 13 6.2.2 Record identifier field (tag = O.l) 13 6.2.3 User application field (tag 0.2) 13 6.2.4 Announcer sequence or feature identifier field (tag 0.3) 13 6.2.5 Fields reserved for future standardization . 13 6.2.6 Recursive tree LINKS field (tag = 0.9) 14 6.2.7 Order of special fie
7、ld tags in the DDR . 14 6.3 Data descriptive fields in level 1 files 14 6.2 Special field tags (tags = O.O to 0.9) . 12 6.2. I. 1 Field control field 6.2.1.2 External file title fi 6.2.1.3 List of Field tag pairs O ISOllEC 1994 All rights reserved. No part of this standard may be reproduced or utili
8、zed in any form or by any means, electronic or mechanical, including photopcopying and microfilm, without permission in writing from the publisher. ISOIIEC Copyright Office Case Postale 56 CH-I21 1 Genve 20 Switzerland Printed in Switzerland i 4853903 0580345 OT5 H O ISO/IEC ISO/IEC 821 I : 1994( E)
9、 6.4 Data descriptive fields in level 2 and 3 files 6.4.1 Tabular summary of data des 6.4.2 Field controls . 6.4.2.1 Data structure code (RP O) 6.4.2.2 Data type code (RP I) . 6.4.2.3 Auxiliary controls (RP 2 6.4.2.4 Printable graphics (RP 4- 6.4.2.5 Truncated escape seque 6.4.3.1 Data field name .
10、6.4.3.2 Array descriptors . 6.4.3.2.1 Numeric array descriptor . 6.4.3.2.2 Subfield labels 6.4.3.2.3 Vector labels . 6.4.3 Data field names, array descriptors and format controls . 16 6.4.3.3 Format controls, . 6.4.4.1 Order of numeric array descriptors . . 19 21 6.4.4 Order of array descriptor 6.4.
11、4.2 Order of cartesian labels 7. I .I Scope of active character sets . 7.2 IS0 2022 coded character set extension 7.2.1 Designation of IS0 202 7.2.1.1 Use in the 7-bit enviro 7.2.2 Designation of default code 23 7.3.3 ISOIIEC 10646 feature identifier field (tag 0.3) . 24 . 26 . 26 Annex A ASN.1 and
12、FTAM Registrations . A.3. I. I Entry number: DDF-I 26 A.3.1.2 Information A.3.1.3 Scope and A.3. I .4 References. . A.3.1.5 Definitions . A.3.1.7 Document semantics . A.3. I .8 Abstract syntactic structure A.3.1.9 Definition of transfer . A. 3. I ,I O Transfer syntax . 27 27 27 A.3.1.11.2 ISO/IEC 82
13、1 I implementation sup A.3.1 .I 1.2.1 The EXTEND operation . . 28 . 28 . 28 iii 9 485L903 0580346 T3L 9 ISO/IEC 821 1:1994(E) A.3.2.5 Definitions . 28 A.3.2.6 Abbreviations . A.3.2.7 Document sema . A.3.2.9 A.3.2.8 Abstract syntactic structure . 29 Definition of transfer 29 A.3.2.9.1 Datatype defini
14、tion 29 A.3.2.9.2 Presentation data values . 29 A.3.2.9.3 Sequence of presentation dat s . 29 A.3.2.10 Transfer syntax . . 29 A.3.2. I 1 ASE specific specifications 30 A.3.2.11.1 ISO8571-FTAM 30 A.3.2.11.2 A.3.2. I I .2. I The EXTEND operation 30 A.3.2.11.2.2 The REPLACE operation 30 A.3.2.11.2.3 Re
15、laxations . 30 ISOIIEC 821 1 implementation support Annex B ISOIIEC 821 1 Application Specifications . B.1 Specification of ISOIIEC 821 I Exchange File Sets 8.2 ISOIIEC 8211 data field description . 8.2.1 General specifications 33 33 B.2.1.1 End of line . 33 8.2.1.2 White space . 33 B.2.1.3 Comments
16、 . 33 8.2.1.4 Quoted strings . 8.2.1.5 Notation 34 B.2.1.6 The INCLUDE construct 34 8.2.1.7 Order of Constructs . 34 8.2.2 File identification . 34 8.2.3 DDR leader specifications . 35 B.2.4 Global default specification 35 8.2.5 Data field specifications B.2.6 Special forms of field constructs . 8.2
17、.6.1 Null first vector label 8.2.6.2 Correspondence of format and last vector label . 37 37 8.2.6.3 Special DDR tagged fields 8.2.7 Special constructs 8.3 Examples of exchange set specification Annex C Informal Introduction to ISOIIEC 8211 C.1 ISOIIEC 8211 File, logical record and field constructs .
18、 C. 1.1 Media record constructs C.1.2 Logical record construct C. 1.3 Logical record structure C.1.3.1 Leader (RP O - 23) . C.1.3.3 Field area . C.1.4 File characteristics and processing . C. 1.3.2 Directory . 43 . .44 44 45 rds 45 C.1.5 Variant logical records C.1.5.1 Long ISOIIEC 82 C.1.5.2 Fixed-
19、formats - repeating leaders and directories C.1.6 ISOIIEC 821 I End-of-data conditions C.1.7 Summary of the logical record and field constructs C.2 Data description and identification . 46 C.2.1 Components of data description 46 C.2.1 .I Data extent . 46 C.2.1.2 Data position . 46 C.2.1.3 Data struc
20、ture 46 C.2.1.4 Data type and syntax . 46 C.2.1.5 Intra-field tree structure . 46 C.2.2 Data identification . . 47 C.2.2.1 Application se 47 . 47 . 47 Annex D Introduction to ISOIIEC 821 I Data Description 48 48 D.2 Consistency of data description and data - validation . 48 D.2.1 Complexity of data
21、description . 48 C.3 File and record contents. C.4 Binary directories . D.l Data description - user data . 4851903 0580347 978 0 ISOAEC ISO/IEC 821 1 : 1994(E) D.2.2 Level 1 data description . D.3.3 Field identification D.5 Intra-record tree structu D.6 Coded character set ext Annex E Examples of Da
22、ta Des E.2.1 Elementary data fields E.2.2 Linear structures 54 54 E.4 Examples of binary forms . E.5 Examples of subfield labelling . E.5.2 Vector labels 57 . 57 . 58 Annex F DDF Hierarchical and Network Da F.1 DDF hierarchical data structures F. 1.1 Forests . 58 F.3 Network data structures G.l .I R
23、elational data base management systems 62 G. 1.2 Hierarchical data base management systems . . 63 G. 1.3 Network data base management systems . 63 63 . 64 G.2 Reduction to relational forms . Annex H Relationship to Other OS1 Work H. 1 OS1 basic reference model H.l .I Other presentation layer conside
24、rations H. 1.2 Remote versus local processing considerations H.2.1 Correspondence of ISO/IEC 821 1 file constructs to FTAM . 66 . 67 H.2.3 Relationship of documents to files H.2.4 File naming H.3 Relationship to other syntax nota H.3.1 Abstract syntax notation on H.3.2 Transfer Syntax Description H.
25、4 Relationship to data base manag H.2 Relationship to FTAM virtual filest H.2.2 ISO/IEC 821 1 access methodology H.5 Bibliography . 68 H.6 Summary of data types in other p . 69 List of figures Figure I - Schematic of ISOIIEC 821 1 File and Logical Records. Figure 2 - File Schematic Representation Fi
26、gure 3 - Logical Record Schematic . Figure 4 - LR Leader Schematic Figure 5 - LR Entry Map Schematic Figure 6 - LR Directory Entry Schemat Figure 7 - File Control Field Schematic Figure 8 - Schematic of Level 2 and 3 Figure F.l - Examples of Ordered Roo Figure F.2 - Generic Structure of a Logical Re
27、cord . Figure F.3 - Instance of a User Data Tree based on F.2 Figure F.4 - Corresponding Binary Tree to the Tree of F.2 . 4853903 0580348 804 D ISOAEC 821 1:1994(E) O ISO/IEC List of tables Table I . Delimiters and Their Uses . 15 Table 2 - Data Descriptive Field Components 15 Table 3 - Extensions o
28、f Bitfield Data Descriptions 20 Table A.2 Information Objects in the Structured Text Document Type 28 Table A . 1 information Objects in the Unstructured Text Document Type 26 O iSO/IEC = Li85L03 0580349 740 M ISO/IEC 821 1:1994(E) Foreword IS0 (the International Organization for Standardization) an
29、d IEC (the International Electrotechnical Commission) form the specialized system for worldwide standardization. National bodies that are members of IS0 or IEC participate in the development of International Standards through technical committees established by the respective organization to deal wi
30、th particular fields of technical activity. IS0 and IEC technical committees collaborate in fields of mutual interest. Other international organizations, governmental and non- governmental, in liaison with IS0 and IEC, also take part in the work. In the field of information technology, IS0 and IEC h
31、ave established a joint technical committee, ISOIIEC JTC 1. Draft International Standards adopted by the joint technical committee are circulated to the national bodies for voting. Publication as an International Standard requires approval by at least 75 % of the national bodies casting a vote. Inte
32、rnational Standard ISOIIEC 821 I was prepared by Joint Technical Committee ISOIIEC JTC 1, hformation fechnology, Subcommittee SC 21, Open systems interconnenction, data management and open distributed processing. This second edition cancels and replaces the first edition (IS0 821 1 : 1985), which ha
33、s been technically revised. The substantive changes made to produce this edition of ISOIIEC 8211 are the following additions: 1. Binary forms for numeric values. 2. Binary leaders and directories. 3. Support for ISOAEC 10646. 4. Definition of FTAM unstructured and structured document types. 5. Conca
34、tenated regular structures. 6. Recursive tree description. 7. A human-readable, alternate form of data field description. The second edition is backwards compatible with the first edition. Annex A forms an integral part of this International Standard. Annexes 8 to H are for information only. vii ISO
35、/IEC 821 1 : 1994( E) 4851703 0580350 ir62 O ISO/IEC Introduction This International Standard has been produced in response to an identified need for a mechanism to allow data structures to be easily moved from one computer system to another, independent of architecture. Data structures required to
36、be inter- changed can vary significantly in complexity and size, and a common method to accomplish these interchanges is desirable. It is also desirable that any medium such as a communication line, a magnetic tape, a disk pack, a flexible disk etc., should be able to be used for the physical interc
37、hange, and that all information necessary to successfully recreate the structure in the target system should be contained within the information transported on the medium. To meet these needs this International Standard specifies medium-independent and system-independent file and data record formats
38、 for the interchange of information between computer systems. This International Standard is intended for use with physical recorded media as well as with communications media. The contents in the user data structure can be of any internationally recognized character set and coding and are interchan
39、ged in a transparent fashion. The intermediate structure through which the information passes is designed for interchange purposes. It can also be used for some forms of general processing and is amenable to direct access methods on high volume, direct access interchange media. This International St
40、andard is a concrete transfer syntax and encoding standard and provides a tool for the description of files containing user data but does not specify the content or order of user data fields or user data records. It does specify a com- prehensive generic form for such records and fields which can ac
41、commodate a wide variety of user needs for both simple and complex user data. An application must design its own instance of a conforming interchange file and all conforming files, both data and data description, will be processable to the field or subfield level by the same software. A user must, o
42、f course, complete the interface to their own application system. The approach used is to define an interchange format into which most information structures and their content can be trans- formed without loss of information, and from which the original structure and content can be retrieved. The in
43、terchange format is suitable both for recording on physical media and transport through a communication system. The data structures supported by the interchange format are elementary data, vectors, arrays and hierarchies. The file struc- tures that can be transformed into the interchange format incl
44、ude sequential, hierarchical and relational. Network structures are not directly supported and additional pre-processing and post-processing are necessary in this case to preserve logical I in ka g es. This International Standard is media independent. It assumes, at a minimum, that the supporting tr
45、ansport system can process fixed length octet strings. It requires a computer processing capability to map the user file or database data to the interchange file. This mapping function has to provide the necessary data and structure conversions. The parameters required to define the selection and co
46、nversion of these data items and structures into the formats specified by this International Standard are outside the scope of the standard. This International Standard requires the use of a basic character set based on IS0 8859-1 and ISOIIEC 6429 in control fields and permits the use of additional
47、character sets in user data fields. This International Standard provides for three interchange levels from which the users may choose based on the complexity of their data structures. The first interchange level supports multiple fields containing simple, unstructured character strings. The second l
48、evel supports the first level and multiple fields containing structured user data comprising a variety of data types. The third level supports the second level and hierarchical data structures. The experience of implementing ISOIIEC 8211 for a variety of applications revealed the need for the change
49、s introduced in this version. Many of the changes give ISOIIEC 821 1 increased versatility and more effective interchange capabilities. Many other changes were made to improve clarity and user acceptance. Technical changes in the standardized interchange supporting this International Standard and changes in the organizational responsibility for this International Standard have led to other extensions. This version provides the user with an improved interchange tool in keeping with the users increasing needs and well integrated into the OS1 environment. The retrieval of archived files
