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Reading Data from File, Named Constants, and Printing Control

Learn to read data from files using Sequential Read and Random Read in RPG programming. Understand how to access named constants, print control, and break up dates into fields. Master techniques like initializing standalone fields and defining data structures effectively.

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Reading Data from File, Named Constants, and Printing Control

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  1. Reading Data from File, Named Constants, and Printing Control Week3

  2. Reading Data from files (Sequential Read) Read sales; Dow not %eof(sales); enddo

  3. Reading data from files(Random Read) • The project file (projpf) has a key field, projid. • To find the record where projid = ‘SUNNY’: projid = ‘SUNNY’; chain projid projpf; if %not found; endif;

  4. Chain using composite key • Syntax Chain (studnbr:semester:coursenbr) studgrades; • The key fields to the file, STUDGRADES are: STUDNBR SEMESTER COURSENBR

  5. Named Constants • Value never changes during processing • No specified length • Type determined by value

  6. Initializing StandAlone Fields Use INZ keyword under keywords • You can initialize a field to a value • Some handy special values: • *sys (system date) • *null • *time (system time)

  7. How Defined Data Structure to break up a date into fields. DdateStruct DS D systemDate D inz(*sys) D struct_year 4S 0 overlay(systemdate:1) D struct_month 2s 0 overlay(systemdate:6) D struct_day 2s 0 overlay(systemdate:9)

  8. Page Overflow • OfLind Keyword and assign an indicator OfLind(*Inof) • Available indicators are: • OA, OB, OC, OD, OE, OF, OG, OV and01 - 99

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