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AcuODBC User's Guide
Version 6.0

6.3.6 HIDDEN Directive

The HIDDEN directive allows you to hide specific data items from end users, while providing normal access to other data items. When you place this directive immediately before a data item in an FD, that item is hidden from end users. The HIDDEN directive applies only to the elementary data item it precedes. Subsequent data items revert to normal read access. Note that you cannot apply the HIDDEN directive to group items and you cannot hide the key.

Syntax

    $XFD HIDDEN   

or

    *(( XFD HIDDEN ))   

In the following FD, "fee" is hidden from users in the resulting table.

           FILE SECTION.   
           FD  qa-file.   
          $XFD COMMENT  This is a sample file demonstrating directives.   
           01  qa-record.   
               03  animal-info.   
                   05  patient-id                  pic x(5).   
                   05  atype                       pic x.   
                   05  ctype redefines atype       pic x.   
                   05  dtype redefines atype       pic x.   
                   05  otype redefines atype       pic x.   
               03  owner-info.   
                   05  phone                       pic x(8).   
                   05  owner                       pic x(30).    
               03  financial.   
                   05  acct_no.   
                       10  year                    pic x(2).   
                       10  seq_no                  pic x(4).   
          *(( XFD DATE=YYYYMMDD, USE GROUP ))   
                   05  last_visit.   
                       10  yyyy                    pic 9(4).   
                       10  mm                      pic 9(2).   
                       10  dd                      pic 9(2).   
          $XFD HIDDEN   
                   05  fee                         pic s9(5)v99.   
          $XFD DATE=YYYYMMDD   
                   05  date_paid                   pic 9(8).   

Note that in the resulting table, the "fee" column no longer appears:

This directive is useful for hiding data like passwords, telephone numbers, and financial information -- whatever information you do not want users to see.

You cannot include a HIDDEN field in a WHENdirective with a TABLENAME clause, due to the complexities of editing or adding records. In this situation, you must add the data, but since the field is hidden, you cannot see it and could add a value that would cause unexpected results. See section 6.3.11, "WHEN Directive," for additional information.

If you add the HIDDEN directive to the FD, you should use the xfdcrypt utility included with AcuODBC to encrypt your XFDs. Otherwise, users could remove this directive to gain access to privileged fields. See section 6.4, "Encrypting XFD Files," for more information.


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