Use of Subfiles
Some typical ways you can make use of subfiles include:
- Display only. The work-station user reviews the display.
- Display with selection. The user requests more information about one of the items on the display.
- Modification. The user changes one or more of the records.
- Input only, with no validity checking. A subfile is used for a data entry function.
- Input only, with validity checking. A subfile is used for a data entry function, but the records are checked.
- Combination of tasks. A subfile can be used as a display with modification, plus the input of new records.
The following figure shows an example of data description specifications for a subfile control-record format. For an example of using a subfile in an RPG program, see Search by Zip Code.
Figure 1. Data Description Specifications for a Subfile
Control-Record Format
*.. 1 ...+... 2 ...+... 3 ...+... 4 ...+... 5 ...+... 6 ...+... 7 ..*
AAN01N02N03T.Name++++++RLen++TDpBLinPosFunctions++++++++++++++++++++*
A R FILCTL SFLCTL(SUBFIL)
A N70 SFLCLR
A 70 SFLDSPCTL
A 71 SFLDSP
A SFLSIZ(15)
A SFLPAG(15)
A TEXT('Subfile Control Record')
A OVERLAY
A 71 ROLLUP(97 'Continue Search')
A CA01(98 'End of Program')
A HELP(99 'Help Key')
A 1 2'Customer Name Search'
A 3 2'Search Code'
A SRHCOD R I 3 14PUTRETAIN
A 5 2'Number'
A 5 10'Name'
A 5 32'Address'
A 5 54'City'
A 5 76'State'
A*
The subfile control-record format defines the attributes of the subfile,
the search input field, constants, and function keys. The keywords you can
use indicate the following:
- SFLCTL names the associated subfile (SUBFIL).
- SFLCLR indicates when the subfile should be cleared (when indicator 70 is off).
- SFLDSPCTL indicates when to display the subfile control record (when indicator 70 is on).
- SFLDSP indicates when to display the subfile (when indicator 71 is on).
- SFLSIZ indicates the total number of records to be included in the subfile (15).
- SFLPAG indicates the total number of records in a page (15).
- ROLLUP indicates that indicator 97 is set on in the program when the user presses the Roll Up key.
- HELP allows the user to press the Help key for a displayed message that describes the valid function keys.
- PUTRETAIN allows the value that is entered in the SRHCOD field to be kept in the display.
In addition to the control information, the subfile control-record format also defines the constants to be used as column headings for the subfile record format.