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Object Relocation File Disclosure Number: IPCOM000109745D
Original Publication Date: 1992-Sep-01
Included in the Prior Art Database: 2005-Mar-24
Document File: 1 page(s) / 39K

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Buquoi, GH: AUTHOR [+3]


A method of locating different parts of a spanned database table object is described.

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

Object Relocation File

       A method of locating different parts of a spanned
database table object is described.

      In prior releases, all database files (except log files) were
created in the main database subdirectory.  The Span Utility allowed
the user to move a table object to a different directory or to span
the object across multiple directories.  With the Span Utility, a
method was needed to track the location of each table object and its
multiple parts.

      The Buffer Pool Component of the OS/2* Database Manager creates
the Object Relocation File (ORF) in the main database directory with
the name "SQL00001.ORF" during database creation.  This flat file
contains an entry for each table object in the database which defines
the location of each of the object's physical files or parts.  Buffer
Pool reads the ORF into memory during database initialization (when
the first application connects to the database) and creates the table
object location linked list (TOLLL) in memory.  Both the TOLLL and
the physical file are updated whenever a table object is created,
deleted, or spanned.  During the processing of any transaction, when
data from a table object is requested, Buffer Pool reads through the
TOLLL to determine the physical location of the data.

      By creating and maintaining the ORF, Buffer Pool is the only
Database Manager component aware of the physical location of any
table objects.  All other components reference data in tabl...