Using Output Specifications

Output specifications are optional for an externally described file; they are not allowed for local files in subprocedures, or qualified files. RPG supports file operation codes such as WRITE and UPDATE that use the external record-format description to describe the output record without requiring output specifications for the externally described file.

You can use output specification to control when the data is to be written, or to specify selective fields that are to be written. The valid entries for the field-description line for an externally described file are output indicators (positions 21 - 29), field name (positions 30 - 43), and blank after (position 45). Edit words and edit codes for fields written to an externally described file are specified in the DDS for the file. Device-dependent functions such as fetch overflow (position 18) or space/skip (positions 40 - 51) are not valid in an RPG program for externally described files. The overflow indicator is not valid for externally described files either. For a description of how to specify editing in the DDS, refer to the DB2 Universal Database for iSeries section of the Database and File Systems category in the i5/OS Information Center at this Web site - http://www.ibm.com/systems/i/infocenter/.

If output specifications are used for an externally described file, the record-format name is specified in positions 7 - 16 instead of the file name.

If all the fields in an externally described file are to be placed in the output record, enter *ALL in positions 30 through 43 of the field-description line. If *ALL is specified, you cannot specify other field description lines for that record.

If you want to place only certain fields in the output record, enter the field name in positions 30 through 43. The field names you specify in these positions must be the field names defined in the external record description, unless the field was renamed on the input specifications. See Figure 162.

You should know about these considerations for using the output specifications for an externally described file:

• In the output of an update record, only those fields specified in the output field specifications and meeting the conditions specified by the output indicators are placed in the output record to be rewritten. Fields not specified in the output specifications are rewritten using the values that were read. This technique offers a good method of control as opposed to the UPDATE operation code that updates all fields.
• In the creation of a new record, the fields specified in the output field specifications are placed in the record. Fields not specified in the output field specifications or not meeting the conditions specified by the output indicators are written as default values, which depend on the data format specified in the external description (for example: a blank for character fields; zero for numeric fields).

*.. 1 ...+... 2 ...+... 3 ...+... 4 ...+... 5 ...+... 6 ...+... 7 ...+... *
OFilename++DF..N01N02N03Excnam++++B++A++Sb+Sa+............................*
OITMREC    D    20
O..............N01N02N03Field+++++++++YB.End++PConstant/editword/DTformat++
O                       *ALL  1 
 *
OSLSREC    D    30
O                       SLSNAM  2 
O                       COMRAT
O                  15   BONUS
 *

 1 

For an update file, all fields in the record are written to the externally described record ITMREC using the current values in the program for all fields in the record.

For the creation of a new record, all fields in the record are written to the externally described record ITMREC using the current values in the program for the fields in the record.

 2 

To update a record, the fields SLSNAM and COMRAT are written to the externally described record SLSREC when indicator 30 is on. The field BONUS is written to the SLSREC record when indicators 30 and 15 are on. All other fields in the record are written with the values that were read.

To create a new record, the fields SLSNAM and COMRAT are written to the externally described record SLSREC when indicator 30 is on. The field BONUS is written when indicators 30 and 15 are on. All other fields in the record are written as default values, which depend on their data type (for example: a blank for character fields; zero for numeric fields).