Browse Prior Art Database

Scheme for Nested Processing of a DL/I Hierarchy

IP.com Disclosure Number: IPCOM000046516D
Original Publication Date: 1983-Jul-01
Included in the Prior Art Database: 2005-Feb-07
Document File: 3 page(s) / 39K

Publishing Venue

IBM

Related People

Wilson, GM: AUTHOR

Abstract

In this article I describe a method for extracting hierarchical data from, for example, DL/I hierarchies. According to the method, a computing apparatus is operated, beginning with the first segment at the top of the hierarchy, to (a) GET a segment from the hierarchy; (b) if the GET is successful, next GET the first subordinate segment at the next (lower) level; (c) if a GET is not successful, next GET the next segment at the previous (higher) level. From this data, rows of extracted data are generated.

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Scheme for Nested Processing of a DL/I Hierarchy

In this article I describe a method for extracting hierarchical data from, for example, DL/I hierarchies. According to the method, a computing apparatus is operated, beginning with the first segment at the top of the hierarchy, to (a) GET a segment from the hierarchy; (b) if the GET is successful, next GET the first subordinate segment at the next (lower) level; (c) if a GET is not successful, next GET the next segment at the previous (higher) level. From this data, rows of extracted data are generated.

A sample path of a typical hierarchy includes a plurality of segments A, B, and C. According to the method, the computing apparatus is operated to get an occurrence of A, and then to get the first occurrence of B within the A, and then to get the first C within the B. Then it is operated to generate a row of extracted data, get the next C within that B, and generate another extract row.

Processing proceeds in this manner until there are no more Cs within that B, then the next B is processed. Processing for this B is the same as for the first B, and proceeds like this for all Bs. When there are no more Bs, the next A is processed, and for this and succeeding As, processing is as described above.

Control Block Structure

Fig. 1 sets forth the arrangement of control blocks used by the computing apparatus to access these hierarchy paths and generate extract rows. The entries of the control block XCB represent the major functions needed to generate an extract, and map very closely to the hierarchy itself. The sample XCB in Fig. 2 shows these entries for the case described above in connection with Fig 1. In particular, there are entries for the DL/I segment acc...