Browse Prior Art Database

Start Using Database With Exclusive Use

IP.com Disclosure Number: IPCOM000035121D
Original Publication Date: 1989-Jun-01
Included in the Prior Art Database: 2005-Jan-28
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Hernandez, R: AUTHOR [+3]

Abstract

This article describes a mechanism that allows an application running in multiple processes to have exclusive use of an OS/2 Extended Edition Database Manager database while sharing access to the database among its parts within the multiple processes.

This text was extracted from a PDF file.
This is the abbreviated version, containing approximately 84% of the total text.

Page 1 of 1

Start Using Database With Exclusive Use

This article describes a mechanism that allows an application running in multiple processes to have exclusive use of an OS/2 Extended Edition Database Manager database while sharing access to the database among its parts within the multiple processes.

The Database Manager views applications as single process. The process connects to the database using a Start Using Database command, and all resource serialization and recovery is done within the context of the process. Applications can obtain exclusive use of the existing tables within the database by locking each table. However, this does not prevent new tables from being created.

There are applications that require exclusive use of a database (the Database Manager Database Utilities, for example). Also, it is necessary to to write the application to run in multiple processes with each process requiring access to the database.

A 'Use' parameter was added to the Start Using Database command to allow the application to specify whether it wishes to exclude other applications from updating the database concurrently.

If shared use is requested, then concurrent updates are allowed, and a subsequent exclusive use request will fail to connect to the database.

If exclusive use is requested, then concurrent updates are prevented from unrecognized users. Exclusive use of the database does provide for other applications which are operating under the same SQLUSER ID to update the databa...