Using Modification Routines
The following set of routines are used to access existing records and ready them for updating. The Modify routines update any values in the record, including any indexes which might have changed due to the updated column values.
With the exception of the 820-UPDATE-<Index> routine, calling one of these routines does not actually modify the record. Instead, it returns the record to the record area fields and sets a switch so that any changes made to the field values are made in the file when you perform an 820-STORE-<FileName> call. Without the 820-STORE-<FileName> call, the changes are not made in the file.
The Modify routines set the <FileName>-SW switch to indicate the outcome of the read. This routine sets the logical value <FileName>-NOTFOUND or <FileName>-FOUND based on the outcome of the read process.