PtrUpdate function

PtrUpdate validates and establishes the pointers that maintain logical relationships. It connects logical children to their logical parents and matches paired logical children to each other. If logical child segments are loaded to a database, a PtrUpdate is required before making any calls to the database. A PtrUpdate is run after loading the physical databases containing the logical children and their logical parents.

Syntax

mfims imsdbu PTRU {database-name|filename}
     [[NO]CLS] 
     [ECHO(keyword,msglvl,stoplvl
     [[NO]INI(filespec)]
     [[NO]LIST(filespec)]
     [LISTOPEN(disp)]
     [[NO]LOG(filespec)]
     [PROGRESS(no-of-segments)]

Parameters

database-name

The name of a database on which the function operates.

filename

The name of a file containing a list of databases on which the function operates.

CLS

Clears the screen before starting the utility. NOCLS prevents the initial clear screen and can be helpful when you are running a series of utilities in a command file.

Default:

NOCLS

ECHO

Controls the display of and interaction with the messages displayed by IMSDBU.

Default:

ECHO(MSGS,4,8)

Sub-parameters

keyword	The category of information displayed. One of the following: ALL Always displays processing messages, input source or detail information and the ending message. Warning and error messages are displayed and stop for user input if the message level is equal to or greater than the msglvl and stoplvl values. MSGS Always displays processing messages and the ending message. No source or detail information is displayed. Warning and error messages are displayed and stop for user input if the message level is equal to or greater than the msglvl and stoplvl values. ERREND Always displays the utility ending message. Warning and error messages are displayed and stop for user input if the message level is equal to or greater than the msglvl and stoplvl values. ENDMSG Displays ending message only if the utility ending return code is equal to or greater than msglvl. A "Press any key to continue" message is displayed and stops for input if the utility ending return code is equal to or greater than the stoplvl. Enter a msglvl and/or stoplvl value of zero to display and/or stop on every ending message. COND Both the warning/error and ending messages are conditional on the msglvl and stoplvl values. Warning and error messages are displayed and stop for user input if the message level is equal to or greater than the msglvl and stoplvl values. The ending message is displayed if the ending return code is equal to or greater than msglvl. You see the message "Press any key to continue" which requires input if the utility ending return code is equal to or greater than the stoplvl. ERRORS You see warning and error messages which require input if the message level is equal to or greater than the msglvl and stoplvl. You do not see the ending message.
msglvl	A value from 4 through 20 to indicate the severity of messages to display.1
stoplvl	A value from 4 through 20 to indicate the severity of messages to stop for user input. 1

¹ Can take the following values:

Value	Category	Example Cause
4	General warning message	A minor coding error in DBD source which DBDGEN can make an assumption about and continue.
6	IMS specific warning message	A warning that a keyword or statement is not supported and is ignored - processing can continue.
8	General severe error	An incorrect coding in DBD source which cannot be compensated for, such as 'no DBD statement'.
10	IMS Option specific severe error	An unsupported feature was defined which cannot be compensated for, such as 'Exceeded some maximum'.
12	Severe error - possible temporary condition	A temporary I/O error such as a 'file locked' or 'database locked' status.
16	Severe error- permanent - likely installation problem	A permanent I/O error, such as an invalid data set name or member name, was input to a utility or an environment variable is not set correctly.
20	Severe error - permanent	An unrecoverable I/O error or some other unexpected error.

INI

Specifies the default directives file.

Default:

None

Sub-parameter

filespec

The name and location of the .INI file containing directives that override the IMSDBU programmed defaults.

Syntax Rules

1. filespec can include a drive and/or directory if required. If you do not specify a drive or directory, IMSDBU looks for the named .INI file in the current directory.
2. Directives listed in the .INI file override the IMSDBU programmed defaults.
3. Directives entered on the command line or interactive screen override directives in the .INI file.
4. Specifying NOINI prevents any .INI file from overriding the programmed defaults.
5. If you specify an .INI file that does not exist, the programmed default directives are used as if NOINI were specified.

General Rules

1. An .INI file is an ASCII text file containing a heading, [IMSDBU] on line 1, starting in column 1, followed by a list of mfims imsdbu directives; one directive per line. A line is terminated by a return or an end-of-file. Comment lines are indicated by an asterisk (*) or semi-colon (;) in column 1. For example:

   [IMSDBU]
   PROGRESS(1000)
   ;use local log
   LOG(C:\MYDIR\MYDB.LOG)

LIST

Controls the location and name of the detail listing file, which includes items such as source listings, completion status, error messages and execution statistics.

Default:

LIST(*.LST)

Sub-parameter

filespec

The name and location to use for the listing file.

Syntax Rules

1. filespec can include a drive and/or directory if required. If you do not specify a drive or directory, IMSDBU creates the listing file in the current directory.
2. NOLIST suppresses the creation of the listing file.
3. To specify a path, you can use the convention of placing a dollar sign ($) in front of the name of an environment variable that represents a path. For example, LIST($ENVVAR\*.DOC) creates a list file of dbdname.DOC in the directory named by the ENVVAR environment variable.
4. Specifying LIST(*.LST) or LIST(*.RPT) causes the listing file to be created in the project listing directory.
5. If no path is specified, the listing file is created in the current directory.
6. If you specify the base name of filespec as an asterisk (*), it is replaced by the DBD name; this allows IMSDBU to provide separate reports for functions that can operate on multiple databases. It also assists in maintaining historical detailed reports by DBD name.
7. Specifying LIST with no filespec is equivalent to specifying LIST(*.LST).

LISTOPEN

Controls the open disposition of the detail listing file.

Default:

LISTOPEN(NEW)

Sub-parameter

disp	The disposition to use. One of: NEW Creates a new listing file or overwrites an existing one. MOD Appends the list output to an existing file or creates a new listing if one does not exist. MOD allows you to maintain a detailed historical record of database functions.

Syntax Rules

1. LISTOPEN is ignored when NOLIST is specified.

LOG

Specifies the IMSDBU activity log, which shows the ending message status for each function.

Default:

LOG(IMSDBU.LOG)

Sub-parameter

filespec

The name and location of the file to use as the IMSDBU activity log.

Syntax Rules

1. filespec can include a drive and/or directory if required. If you do not specify a drive or directory, the listing is created in the current directory.
2. Specifying NOLOG suppresses the log file output.

General Rules

1. The log file is created if it does not exist.
2. The log file is historical with the most recent entries written to the end of the file.
3. As the log file grows in size over time, it might require deletion periodically.

PROGRESS

Controls the frequency of progress reporting.

Default:

PROGRESS(200)

Sub-parameter

no-of-segments

A value between 0 and 9999 indicating the number of segments to process before displaying a progress message. 0 disables progress reporting.

Syntax Rules

1. We recommend that you do not reduce the number of segments specified to a value below its default of 200. Very small values measurably reduce the performance of the database function.
2. For relatively fast systems, setting the value higher (such as to 1000 or larger) might improve performance slightly.

General Rules

1. The progress message could show the number of segments processed, or the percentage complete and an estimate of the time remaining.

Input

The input is the DBD name of a physical DBD that defines logical children segments. The IMSDBU Load function must have been performed for this DBD name and for any databases containing logical parents for the logical children. A database which defines logical children does not require PtrUpdate if no logical child segments were loaded to the database.

An error message is issued if you attempt to run PtrUpdate for:

• A DBD which does not define any logical children
• A DBD name which was not input to the IMSDBU Load function

A PtrUpdate can be run for exclusive use databases. IMSDBU does not support PtrUpdate or Load for User Exit databases.

Output

Updated database data files for the input DBD name and any database referenced by logical child occurrences in this database. Once PtrUpdate completes, the databases can be accessed from application programs using any of the supported physical and logical access paths.

Segments

The PtrUpdate function creates the pointers that establish logical relationships. Logical pointers are created between a logical child and its logical parent and between paired logical children. If two of these logically related segments cannot be connected, an adjustment is made. The adjustments ensure that all of the logical pointers in a database refer to valid segments.

The two adjustments that might be performed are:

• A logical child segment is deleted when its logical parent segment does not exist. When this occurs, the logical child segment data and the logical parent concatenated key are included in the detail report listing.
• If a paired segment to a logical child does not exist, it is created. The paired logical child is created in the same way it would be created for an application ISRT call.

The number of segments deleted and created because of these adjustments is included in the detail report listing. The number of logical child segments updated with a valid logical parent pointer is also included in this report. These counts are listed by segment name.