HP 3000 Manuals HP 3000 Manuals
DBChange Plus Enhancements
by Bharati V. Desai
Commercial Systems Division
MPE/iX Release 5.0 includes significant enhancements to TurboIMAGE/XL,
which now constitutes a major component of HP IMAGE/SQL. Several of these
enhancements affect the TurboIMAGE/XL utility programs and related
maintenance products, such as DBChange Plus. DBChange Plus version
A.02.00 includes enhancements to keep pace with TurboIMAGE/XL, as well as
enhancements you requested.
This article is a general overview of the major enhancements to DBChange
Plus. For detailed information on all enhancements and bug fixes in this
version, use the new DBChange Plus NEWS command.
For DBChange version A.02.00, the enhancements are:
* Support for Dynamic Data Set Expansion
* Faster Capacity Changes for Detail Data Sets
* Conversion of Change File Format
* The new SHOW command
* The new NEWS command
* Better Error Messages
Support for Dynamic Data Set Expansion
The major enhancement in version A.02.00 is the support for Dynamic Data
Set Expansion, which has been one of the most requested enhancements by
TurboIMAGE/XL users. As the name implies, it allows a detail data set
(not a master data set) to be expanded dynamically during DBPUT when the
detail data set space is exhausted. Unlike before, your application will
not be aborted and you will not need to increase the capacity before
resuming your application. However, to use this enhancement, you must
let TurboIMAGE/XL know of certain required information such as the set's
maximum capacity, initial capacity, and the increment to be applied every
time the capacity is exhausted. For existing databases, you can use
DBChange Plus to furnish this essential information to TurboIMAGE/XL.
The commands CHANGE CAPACITY, REPACK SET, and ADD SET allow specification
of maximum, initial, and incremental capacity.
The REVIEW CAPACITY command now reports maximum, initial, incremental,
and current capacity.
The new CONTROL PERCENTFULL option facilitates reducing the set size when
the entry count falls below a minimum percentage of current capacity and
for expanding the set when the entry count exceeds a maximum percentage
of maximum capacity.
For detailed information on each of these commands, as well as syntax,
use the HELP command.
The restructure of the database for dynamic data set expansion requires
TurboIMAGE/XL version C.05.00 or later.
Faster Capacity Changes for Detail Data Sets
This enhancement eliminates the need to rebuild the set file (as
previously done by copying all the data to a 'new' temporary job file)
when only the data set's capacity has to be changed. This applies to all
details, whether or not dynamic expansion is specified for the set.
When reducing the capacity (no REPACK), this feature is available on all
MPE/iX releases. When expanding the capacity, this feature is only
available on MPE/iX Release 5.0 or later.
Conversion of Change File Format
The internal format of the change file has changed, so change files
created by previous versions of DBChange Plus cannot be used with version
A.02.00. However, it is now possible to have DBChange Plus convert the
change file to the new format. In session mode, DBChange Plus will
prompt you if you want the change file to be converted. In batch mode or
when using the XEQ command, you can use either of the following two
methods:
1. Use SETJCW AUTOCVCF n, where n is greater than zero.
2. Put the keyword AUTOCV in the INFO= parm of the RUN command. For
example,
RUN DBCPLUS.PUB.SYS;INFO="AUTOCV".
This enhancement in version A.02.00 is independent of TurboIMAGE/XL and
any MPE/iX release.
SHOW command
The new SHOW command gives information on the versions of TurboIMAGE/XL
and DBChange Plus installed on the system. In addition, it displays the
TurboIMAGE/XL features affecting DBChange Plus currently available on
your system. The features displayed are those implemented in MPE/iX
Release 4.0 or later. Use HELP SHOW to get details about the command.
This enhancement is independent of TurboIMAGE/XL.
NEWS command
The new NEWS command gives current and cumulative information by versions
on all enhancements, as well as bug fixes made in the product. Use HELP
NEWS to get details about the command.
This enhancement is independent of TurboIMAGE/XL.
Better Error Messages
Another useful enhancement is to give meaningful error messages
pertaining to TurboIMAGE/XL and file system errors encountered while
using DBChange Plus. In addition to reporting the error number, the
message text for that error is also given whenever possible.