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Building an EBCDIC Key

IP.com Disclosure Number: IPCOM000082525D
Original Publication Date: 1974-Dec-01
Included in the Prior Art Database: 2005-Feb-28
Document File: 3 page(s) / 38K

Publishing Venue

IBM

Related People

Daniel, CJ: AUTHOR [+6]

Abstract

A method is provided for allowing a terminal user to dynamically build EBCDIC keys needed to access any segment in a data base(s). Using a look-ahead feature, the technique relieves the terminal user from knowing any of the required segment EBCDIC keys. This is accomplished with a rules driven module, which gathers the needed information about a segment from a rule. Since the module is externally driven, it does not have to be modified when new segments are added, deleted or modified in a data base.

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Building an EBCDIC Key

A method is provided for allowing a terminal user to dynamically build EBCDIC keys needed to access any segment in a data base(s). Using a look- ahead feature, the technique relieves the terminal user from knowing any of the required segment EBCDIC keys. This is accomplished with a rules driven module, which gathers the needed information about a segment from a rule. Since the module is externally driven, it does not have to be modified when new segments are added, deleted or modified in a data base.

To access a particular occurrence of a segment in a data base, an EBCDIC key for that segment must be supplied. Therefore, a terminal user through some program must supply the key of the segment to be retrieved, updated, added or deleted. In a data base system, there are thousands of segments, each with a unique key. This makes it almost impossible for a terminal user to remember the key for the segment to be accessed, without either writing it down or referring to a listing. The longer the key, the more time consuming and frustrating it is for the user.

To solve this problem, a key selection rule is provided for each segment in the system's data bases. The key selection module is driven by the rule of the segment to be accessed as to the order and type of processing.

The rule contains the following type of information: 1. The name of the display format to use, in requesting the entire key of the segment to be accessed in the data base. 2. The name of the display format to use to show all the keys under some parent segment. 3. Flag information to describe all the key fields and pertinent data fields within a segment. 4. Length of the key. 5. Length of each field in the makeup of the key. 6. Location of the field within the overall key.
7. The input and output locations of the field in the I/O area. 8. Text data to be placed in the display format. 9. Other miscellaneous data, such as segment level or field description of nonkey data in a segment.

The module loads the proper rule obtained from input parameters and stores the rule until the key selection process is complete. The key selection process requires one or more interactions with the user at the terminal, depending upon the key information initially entered.

The initial key selection display shows by name all the keys required to access the target segment. In most instances, the rule requires the root level segment key to be entered by the user. Any other keys requested may be left blank or entered at the option of the terminal user. The following example demonstrates key selection (see the figure).

In this example, the terminal user wants to view the data in the bill of...