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Support of Multiple SQL Isolation Levels in REXX

IP.com Disclosure Number: IPCOM000121677D
Original Publication Date: 1991-Sep-01
Included in the Prior Art Database: 2005-Apr-03
Document File: 2 page(s) / 82K

Publishing Venue

IBM

Related People

Boykin, JR: AUTHOR

Abstract

Disclosed is the method for support of the three cursor isolation levels in the OS/2* Extended Edition Database Manager for use in the SAA Procedures Language (REXX). This method emphasizes performance and minimal, required, user authorization. BACKGROUND

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Support of Multiple SQL Isolation Levels in REXX

      Disclosed is the method for support of the three cursor
isolation levels in the OS/2* Extended Edition Database Manager for
use in the SAA Procedures Language (REXX).  This method emphasizes
performance and minimal, required, user authorization.
BACKGROUND

      The Database Manager supports three isolation levels:
Repeatable Read, Cursor Stability and Uncommitted Read.  An isolation
level determines how data is locked or isolated from other processes
while the data is being accessed.  See the "IBM Operating System/2
Extended Edition Version 1.2 Database Manager Programming Guide and
Reference Volume 1: Guide" for a discussion of the three isolation
levels.  In the precompiled languages supported by the Database
Manager, these isolation levels are chosen by the application
programmer or user when an application program is precompiled or
bound.  Each individual .bnd file which individually relates to a
unique package in the Database Manager has a specific isolation
level.  In the Database Manager's support of SQL in REXX,
precompilation is not available.  From the user's point of view,
there is no precompilation performed.  However, the Database Manager
must still support the three isolation levels.

      Binding of an application requires an authorization in the
database privilege class.  In order to support the three isolation
levels with one application program, a database privilege of bindadd
would be required for each user executing a REXX program.  This is
unacceptable.  Execution of an application, however, only requires an
authorization within the package class of execute.  The package class
of authorization is a much finer granularity of authorization than
the database class of authorization.  It was decided that the
execution of a REXX application should require the minimal level of
authorization necessary.  However, as stated above, this is not
possible with a single supporting application....