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Method of retaining position in a result table which is persistent across closed cursors

IP.com Disclosure Number: IPCOM000031861D
Original Publication Date: 2004-Oct-14
Included in the Prior Art Database: 2004-Oct-14
Document File: 1 page(s) / 26K

Publishing Venue

IBM

Abstract

Method of retaining position in a result table which is persistent across closed cursors

This text was extracted from a PDF file.
This is the abbreviated version, containing approximately 65% of the total text.

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Method of retaining position in a result table which is persistent across closed cursors

Problem: Online transaction processing (OLTP) applications have the greatest need for scrolling - and they also have the greatest need for concurrency. Consequently, CICS applications use Pseudoconversational transactions - ie. each invocation of the transaction opens a cursor fetches many rows, displays them on the screen and deallocates - losing position, closing cursor etc. in the interest of not holding resources.

Solution:It would be valuable if the database management system could return a bookmark that the pseudoconversational transaction could return with as a token and the database management system could resume scrolling at the position prior to closing the cursor. The book mark will be validated ensure it belongs to the same cursor and it has not been tampered with and there is no exposure regarding access authority.

Since the cursor is closed, the persistent book mark is vulnerable to changes in the data table while the cursor is closed because rows can be deleted, updated or inserted in the position indicated by the bookmark. However, the applications expect this and it can handle the condition.

The bookmark will be a unique hash value generated from a combination of system id, timestamp, transaction identifier, authorization id, database identifier, record identifier, table name, cursor name, physical row position for table scan, index key for index scan and a s...