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Variable Character Conversions

IP.com Disclosure Number: IPCOM000060406D
Original Publication Date: 1986-Apr-01
Included in the Prior Art Database: 2005-Mar-08
Document File: 2 page(s) / 13K

Publishing Venue

IBM

Related People

Weber, O: AUTHOR

Abstract

IMSADF II (Information Management System Application Development Facility Version 2) is an application generator which runs under IMS. As an application program, it can automatically read data from a screen, manipulate the data, perform data base updates, and write the screen back to IMS, as well as perform various other data processing functions. In previous versions of IMSADF, there was no capability to process a field in variable character (VARCHAR) format. VARCHAR fields begin with a two-byte binary length followed by up to 253 bytes of character data. The two-byte binary length determines how many bytes of the following character data constitute the field value.

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Variable Character Conversions

IMSADF II (Information Management System Application Development Facility Version 2) is an application generator which runs under IMS. As an application program, it can automatically read data from a screen, manipulate the data, perform data base updates, and write the screen back to IMS, as well as perform various other data processing functions. In previous versions of IMSADF, there was no capability to process a field in variable character (VARCHAR) format. VARCHAR fields begin with a two-byte binary length followed by up to 253 bytes of character data. The two-byte binary length determines how many bytes of the following character data constitute the field value. Since IMSADF did not recognize the VARCHAR format and perform appropriate data conversions, VARCHAR fields could not be read, manipulated, displayed, written, etc. Any attempt to process a VARCHAR field could, at best, result in an error indicating that the field had invalid character data. This also created the potential for abends due to not recognizing the first 2 bytes as a halfword length. This problem was overcome in IMSADF II Version 2 by inventing a new data conversion interface which converts VARCHAR fields to/from other data types. Specifically, the new program can move a VARCHAR field to/from an alphanumeric field, a numeric field, an alpha field, a decimal field, a data field, or a hexadecimal field. The most critical of these conversions is the conversion from alphanumeric to/from VARCHAR because this allows IMSADF to format and deformat VARCHAR data base fields and display them. The conversion is accomplished by changing the data pointer to point to the first byte of character data instead of the halfword length. Then conversion takes place as though it were an alphanumeric field, substituting the halfword length of the source field for the rule definition of that field, i.e....