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Browse Prior Art Database

File Organization for Both Context and Line Number Editing

IP.com Disclosure Number: IPCOM000075996D
Original Publication Date: 1971-Dec-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 3 page(s) / 42K

Publishing Venue

IBM

Related People

Koster, LR: AUTHOR

Abstract

In a time-sharing system, in order to add new records to an existing file or to change, replace, or delete records, a data editing facility must be provided. Consequently, it is necessary to organize work files so that records can be easily accessed, usually by indexed access methods requiring a statement sequence number (often called a key field) embedded in the data portion of the record. The data organization and processing described herein provides for editing operations, regardless of the presence of a key field within the input records.

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File Organization for Both Context and Line Number Editing

In a time-sharing system, in order to add new records to an existing file or to change, replace, or delete records, a data editing facility must be provided. Consequently, it is necessary to organize work files so that records can be easily accessed, usually by indexed access methods requiring a statement sequence number (often called a key field) embedded in the data portion of the record. The data organization and processing described herein provides for editing operations, regardless of the presence of a key field within the input records.

Fig. 1 shows the overall data organization comprised of equal size physical blocks containing index pointers 10 or data records 11. Accessing the actual data records always begins by using the first or only index block. The index entries in the index block locate the blocks that contain the data records. It is also possible to have more than one index block, where the highest level index block contains pointers to other index blocks which in turn point to the blocks containing the data records. The index structure is open-ended as to the number of levels and is always in the form of a balanced tree.

Fig. 2 shows the relationship between the possible record formats in the users data collection and the format of the records as they are contained in the data blocks of a work file organized according to the principles herein. Notice that the input records may or may not contain a statement sequence number. However, all records in the work file contain a binary key value as a prefix, which denotes and determines the logical position of that record within the data set. Also, the format of the records in the work file is standardized so that fixed-length record processing becomes a subset of variable-length record processing.

Fig. 3 shows how the work file is constructed by copying any existing user records into the work file. If the records of the user contained embedded statement numbers, the key prefix takes on the same value as the embedded sequenc...