Select option 3. Undo changes to
undo the changes you made to the database.
About this task
As soon as changes are made to the database, they are
entered in the UNDO tables. If IMS Database
Repair Facility ends
for any reason, upon restart of IMS Database
Repair Facility these
UNDO entries are visible and you can execute them to reverse the original
change to the database. However, after the restart of IMS Database
Repair Facility,
the UNDO tables for a particular DBD are reallocated when you enter
option 2. View/Update database to
work with that DBD again.
Therefore, it is recommended that
after you make pointer changes with IMS Database
Repair Facility,
you run the Pointer Checker utility to determine if any errors were
introduced. If errors occur, restart IMS Database
Repair Facility and
immediately select option 3. Undo changes from
the Main menu.
Procedure
Select option 3. Undo changes in
the Main menu and
press Enter.
In the Select IMS system panel,
select the IMS system ID that
is associated database changes that you want to undo.
Enter
an S in the input field that corresponds to
the IMS system ID. Then, press
Enter.
Figure 1. Select IMS system panel
Select IMS system
Command ===>
S Select IMS system ID. END to exit
IMS ID Release
_ IMSA 15.1
_ IMSB 14.1
_ IMSC 14.1
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In the Specify database panel,
specify the database name or, for a partitioned database, the master
DBD name in the DBD name field.
Then, press Enter.
Figure 2. Specify database panel
Specify database
Command ===>
Specify field. END to exit
IMS ID . . IMSA
IMS release . . 15.1
DBD name . . SMPORDP1
If you specify the master DBD name of a partitioned database, Partition Selection List panel
is displayed. Select a partition in the panel by entering an S for
the partition. Then, press Enter.
In the Undo changes panel,
locate the change that you want to undo.
This panel lists the changes that were made to the database. The most recent change is listed
first (before the Previous updates section) and the other changes are listed
in the Previous updates section. The changes are shown in LIFO order, that
is, the more recent changes are at the top of the list, and the oldest changes are at the bottom of
the list. Use PF8 and PF7 to scroll through the list.
You can undo only the change that is shown above the Previous updates
section. To undo a change, enter an S in the input field of a data line, and
then press Enter. If you undo a change, the After and
Before data lines of the next most recent change are moved to the current
area. Because you can undo only the current and most recent changes, you must undo the changes in
the order they were performed. However, by specifying the block RBA or data set group, you can limit
yourself to undoing the changes for just one block address or one data set group even if you made
changes to multiple blocks or data set groups. You can locate the block RBA or data set group by
scrolling through the list of previous updates.
If
the same area was modified several times, it is listed once for each
change in the list in the Previous updates section.
To reverse one of these changes, you must reverse the most recent
changes until you reach the data line you want to undo.
Figure 3. Undo changes
panel
Undo changes
Command ===>
S Select from list then ENTER to undo that change in database.
DBD: SMPORDP1 DBORG: HIDAM DSORG: OSAM Lrecl: 1690 CI-Size: 1690
Specify DSG . . Blk RBA .
S Select DSG Offset Seg.code Seg.name Update time
01 0020 01 SMP00210 20/07/29 13:25:33
Blk RBA . D34
Current : F9C8E4E8C2C1D9C46B40C7C5D6D9C7C540404040404040404040404040404040
Before : F9C8E4E7C2C1D9C46B40C7C5D6D9C7C540404040404040404040404040404040
----------------------------- Previous updates -------------------------------
DSG Offset Seg.code Seg.name Update time
01 0160 01 20/07/29 13:12:24
Blk RBA . 13CE
After : 40404040404002000000000000000000D2C5E7F0F0F0F0F0F0F640C4C5D7F140
Before : 40404040404002000000000000000000D2C5E8F0F0F0F0F0F0F640C4C5D7F140
02 0000 01 20/07/29 13:10:52
Blk RBA . D34
After : 03A400000100000008EC000000000000087E0000080400000804D2C4E8F0F0F0
Before : 03A400000100000008EC000000000000087E0000080400000804D2C5E8F0F0F0
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This panel contains the following
fields:
DBD
The name of the database, or for a partitioned database, the name of the
partition.
DBORG
The database organization type.
DSORG
The organization type of the data set.
Lrecl
The record length.
CI size or Blk size
The size of the control interval or block.
Specify DSG
If you specify a data set group number or an area number on this line, only changes from that
data set group or area are displayed. If you want to undo only the changes in one data set group or
one area, specify a DSG.
You can determine the data set group number or the area number by
checking the value that is shown for DSG in the list of changes that are shown in the
Previous updates section.
Specify Blk RBA or Specify CI RBA
If you specify a block RBA on this line, only changes from that block are displayed. If you made
changes to multiple blocks but want to undo only the changes in one block, specify an RBA.
You
can determine the block address by checking the value that is shown for Blk RBA in the list of
changes that are shown in the Previous updates section.
Select (S)
Enter an S to undo the change that is displayed. You can undo
only the current change.
DSG
The data set group number or, for a DEDB, the area number.
Offset
The offset of the change from the beginning of the segment.
Seg.code
The code of the active segment.
Seg.name
The segment name.
Update time
When the change was made. Both a date and a timestamp are displayed.
Blk RBA or CI RBA
The relative byte address of the block.
Current
The changed value of the data. For the most recent change, this
field is labeled Current. You can undo only the change
in the Current line. For each block, changes
must be undone in the reverse order they were performed. That is,
the most recent change must be undone before you can undo the change
that preceded it.
Before
The former value of the data at the same location. The data content
shows the data before it was replaced by what is shown on the Current or After line.
What to do next
After the change is undone, the panel is refreshed, and
contains a message that the database was successfully updated. The Current line
now shows the present status of the database.
To return to the Main menu, press END several times until the Main menu is displayed.