Robelle | Products | Library | Support | Partners | Contact Us | Site Map

Suprtool and the Year 2000

Suprtool often has to process dates in both the twentieth and twenty-first centuries. If you include the century in your dates, Suprtool should behave as most users expect. If you do not include the century in your dates, how Suprtool behaves will depend on your specific application and data.

The rest of this FAQ discusses these Suprtool topics:

What If I Have Four-Digit Years?

If your dates have four-digit years, Suprtool should work as expected. Selection based on the $today or $date features will select dates in both the twentieth and twenty-first centuries. Dates that do not collate correctly (e.g., MMDDCCYY) will not be accepted by Suprtool's If command in relative selections (e.g., <, <=, >, or >=). If you have these date formats you should use the new $stddate function that converts them to CCYYMMDD dates. Suprtool, as it has always done, will continue to sort dates based on their numeric value, not on any implied date order.

In Suprtool 4.0, we introduced some new command-parsing features that let you control how Suprtool parses the year component in the $date function. You can either use two-digit years by applying a cutoff rule or you can force all years into a four-digit format.

What Does Set Date Cutoff Do?

When used with four-digit years data values to two-digit $date values, Date Cutoff tells Suprtool what century to use in the constant date value of the $date function. This setting only affects the date values generated by the $date function in the If and Extract commands.

Before version 4.0, Suprtool assumed a value of 19 for the century of a user-specified $date with a two-digit year. For example:

      >item date-field,date,ccyymmdd
      >if date-field <= $date(40/12/26)
The $date function in earlier versions of Suprtool would have converted the user-specified $date to 1940/12/26 for comparison to the date field format of CCYYMMDD. With Set Date Cutoff xx, Suprtool now assumes a value of 20 for the century if the two-digit year specified in the $date function is less than or equal to the value of Set Date Cutoff. For example:
      >set date cutoff 50
      >item date-field,date,ccyymmdd
      >if date-field <= $date(40/12/26)
In this case Suprtool assumes the full $date to be 2040/12/26. Conversely, if the value of Set Date Cutoff is 40 or less, then the assumed full $date would be 1940/12/26. The default value of Set Date Cutoff is 10.

We recommend always providing a four-digit year when using the $date function. For reasons of backward compatibility, however, we introduced the Set Date Cutoff command. See Set Date ForceCentury for more information.

What Does Set Date ForceCentury Do?

When used with four-digit years, Set Date ForceCentury On does not allow a YY date to be entered in the $date function; it forces the user to enter a full CCYY date.

     >set date forcecentury on
     >item date-field,date,ccyymmdd
     >if date-field >= $date(96/12/10)

   Error: You must specify the century or Set Date ForceCentury off
The default value for Set Date ForceCentury is Off.

What If I Have Two-Digit Years?

If you have dates with two-digit years, these two main solutions can make your application ready for the year 2000:
  1. Convert all of your date data into four-digit years and modify your programs to process four-digit years, or

  2. Assume that some dates are in the twentieth century and others are in the twenty-first (this is usually called date windowing).
In the first solution, you need to change all the Suprtool Item commands with two-digit years to a four-digit format. If you have not already done so, you may want to isolate all the Item commands from each input source into a single file (e.g., one file for each dataset in every database of your application or just one file for every database). Suprtool 4.1 introduced the nesting of usefiles, which makes this approach even easier (e.g., one database usefile can include each dataset usefile with a list of Item commands). You may also want to use Suprtool to change your actual data from a two-digit year to a four-digit format. See the Can Suprtool Convert Two-Digit Years to a Four-Digit Format? section of this FAQ for more details.

If you do not include the century in your dates (the second solution above), you will have the following problems:

What Is Wrong with Two-Digit Years?

Currently, the date format of YYMMDD collates (sorts) correctly if the date is not after 1999. If the current date is December 10, 1996 for example, its numerical value (961210) is less than the value for December 10, 1997 (971210).

At the turn of the century, dates in the YYMMDD format (or YYMM) will no longer sort correctly because the numeric values of dates in the 21st century will be sorted before date values in the 20th century. For example, the numeric value of 001210 (December 10, 2000) will come before 961210 (December 10, 1996) in the sort sequence. Consequently, if a date after 1999 is stored in a YYMMDD format, a relative operation such as

      >if date-field >= $date(96/12/10)
will not select the date of December 10, 2000. You will need to use the $stddate function to make this task work correctly.
      >if $stddate(date-field) >= $date(96/12/10)
will select the date of December 10, 2000.

How Do $Today and $Date Work?

Suprtool's date functions ($date and $today) are a short-hand method of generating a numeric constant. For example, the following date selection:
     > item invoice-date,date,YYMMDD
     > if invoice-date < $today
is exactly the same as
     > if invoice-date < 980401        {on 1 April 1998}
Suprtool selects records on the numeric value of the field, not on the implied date value. If we move the calendar ahead to January 1, 2000 and repeat the commands above, the result would be the same as if
     > if invoice-date < 000101        {on 1 January 2000}
had been typed. If there were some invoice dates from the previous century (e.g., 990101 for December 1, 1999), they would not have been selected.

What Does Set Date Cutoff Do?

When used with two-digit years, Date Cutoff tells Suprtool what century to use when the $stddate function is converting your two-digit years to the standard CCYYMMDD format. The setting tells which year starts getting "19" as the century, all years lower than this setting get "20" as the century. e.g.

    > set date cutoff 30
    > item invoice-date,date,yymmdd
    > if $stddate(invoice-date) <= $date(*+4/*/*)

In this case all invoice dates with a yy value between 30 and 99 will have 19 as the century. All invoice dates with a yy value of less than 30 will have 20 as the century generated by the $stddate function.

Will Suprtool Generate an Error for Two-Digit Year Dates?

Sometimes. Because dates after 1999 do not collate properly for the YYMMDD and YYMM formats, the If command in version 4.0.11 and later will produce an error when the following set of conditions exist:

  1. the year specified in a $date or $today function is after 1999
  2. the date format is YYMMDD or YYMM
  3. a relative operation (e.g., <, <=, >, or >=) is being performed
  4. and $stddate function is not being used
      >item enddate, date, yymmdd
      >if   enddate >= $date(*+4/*/*)        {21st century date}
     Error:  Cannot use a date beyond 1999 for this format
Although this is the default operation in Suprtool 4.1, it can be overridden with the following new Set command:
      >set date ifyy2000error off
This command tells Suprtool to allow the previously described relative operations and avoid the error message. While you can override the error check, the behavior of $today and $date has not changed.

The recommended solution is to used the new $stddate function to convert the two-digit year into a four-digit year.

      >if $stddate(enddate) >= $date(*+4/*/*)

How Do I Use $Today and $Date with YYMMDD Dates?

If you want Suprtool to select dates in a YYMMDD format for $today or $date functions, you need to use one of the following solutions:
  1. Change the date storage format by including the century in all datasets and data files so that you can use the following Item command:
             > item invoice-date,date,CCYYMMDD
  2. Perform the above step every time date selection is required. This can be done by using the $stddate function that adds the century component to the dates in a CCYYMMDD format.

See the sections How Do I Convert a J2 Date from YYMMDD to CCYYMMDD? and How Do I Convert an X6 YYMMDD Date to an X8 CCYYMMDD Date? for more details on converting two-digit years into a four-digit format.

Why Doesn't Suprtool Support 'Windowing' during Sorts?

Most Suprtool users are converting their dates to include four-digit years. Enhancements that enable Suprtool's Sort command to handle two-digit years with a windowing approach would require an enormous R&D investment. If you have specific needs that are not being addressed by Suprtool in your Year 2000 projects, please contact Let us know how you plan to handle dates both now and in the next century as well as how you see Suprtool fitting into your plans.

Can Suprtool Convert Two-Digit Years to a Four-Digit Format?

Suprtool is capable of converting dates from one format to another through a variety of features. We will show you how Suprtool can convert common dates without a century component to dates that include the century. While Suprtool can convert your data, it is up to you to change your programs. Adager, a third-party program for changing IMAGE database structures, has the ability to change date fields. Suprtool can convert data in IMAGE databases, flat files, self-describing files and KSAM files.

How Do I Convert a J2 Date from YYMMDD to CCYYMMDD?

The $stddate function can convert six-digit date formats to CCYYMMDD. But what if all the dates are not actually dates, but some dates are filled with 9s as a flag to an application?

Consider this dataset with two date fields, J2 items and in the date format YYMMDD.

  Database: STORE.DB.GREEN

      D-SALES          Detail    Set 5
         Entry:                     Offset
            CUST-ACCOUNT         Z8      1  (!M-CUSTOMER)
            DELIV-DATE           J2      9
            PRODUCT-NO           Z8     13  (M-PRODUCT)
            PRODUCT-PRICE        J2     21
            PURCH-DATE           J2     25
            SALES-QTY            J1     29
            SALES-TAX            J2     31
            SALES-TOTAL          J2     35
      Capacity: 602 (14)  Entries: 10  Highwater: 10  Bytes: 38
First, we need to know and understand our data. Are there any invalid dates? If so, does the value have some other logical meaning?
    >get d-sales
    >item deliv-date,date,yymmdd
    >item purch-date,date,yymmdd
    >if $invalid(deliv-date) or $invalid(purch-date)
    >GET D-SALES (9) >OUT $NULL (0)
    CUST-ACCOUNT    = 10010          DELIV-DATE      = 999999
    PRODUCT-NO      = 50513001       PRODUCT-PRICE   = 19220
    PURCH-DATE      = 999999         SALES-QTY       = 2
    SALES-TAX       = 2691           SALES-TOTAL     = 21910

    >GET D-SALES (10) >OUT $NULL (1)
    CUST-ACCOUNT    = 10010          DELIV-DATE      = 125213
    PRODUCT-NO      = 50513001       PRODUCT-PRICE   = 19220
    PURCH-DATE      = 1              SALES-QTY       = 2691
    SALES-TAX       = 21910          SALES-TOTAL     = 21910

    IN=10, OUT=2.  CPU-Sec=1.  Wall-Sec=1.
In this example, we see two records that do not contain proper dates. The first record contains all 9s, which is probably used as some sort of flag. We may need to add 99 in front of these dates. But the second record is obviously wrong. We can use Dbedit to correct this record before converting the other dates. We need to know our data to properly convert to a new date format.

Once all the incorrect dates are fixed, we can start converting. We can add a prefix of 19 or 20 to all the appropriate dates by using the following Extract statement. Please note that we are updating this directly. In case we need to redo this task, we only convert those dates that have not yet been converted. In this example we set the cutoff year to 30 so any dates before 30 will have '20' as the century and the others will have '19'.

       >get d-sales
       >set date cutoff 30
       >item purch-date,date,yymmdd
       >item deliv-date,date,yymmdd
       >if not $invalid(purch-date) and not $invalid(deliv-date)
       >ext purch-date = $stddate(purch-date)
       >ext deliv-date = $stddate(deliv-date)
We have now converted all the J2 YYMMDD dates to a CCYYMMDD format and added the correct century to the date.

How Do I Convert an X6 YYMMDD Date to an X8 CCYYMMDD Date?

The following Suprtool task shows how we can generate a new file in a different date format for a new database. Consider the deliv-date and purch-date fields of the d-sales dataset:

      D-SALES          Detail    Set 5
         Entry:                     Offset
            CUST-ACCOUNT         Z8      1  (!M-CUSTOMER)
            DELIV-DATE           X6      9
            PRODUCT-NO           Z8     15  (M-PRODUCT)
            PRODUCT-PRICE        J2     23
            PURCH-DATE           X6     27
            SALES-QTY            J1     33
            SALES-TAX            J2     35
            SALES-TOTAL          J2     39
      Capacity: 611 (13)  Entries: 15  Highwater: 15  Bytes: 42
We want to convert to a date format that has room for the century (CC) at the beginning of deliv-date and purch-date:
     Database: STORE.DB.ACCOUNT

      D-SALES          Detail    Set 5
         Entry:                     Offset
            CUST-ACCOUNT         Z8      1  (!M-CUSTOMER)
            DELIV-DATE           X8      9
            PRODUCT-NO           Z8     17  (M-PRODUCT)
            PRODUCT-PRICE        J2     25
            PURCH-DATE           X8     29
            SALES-QTY            J1     37
            SALES-TAX            J2     39
            SALES-TOTAL          J2     43
      Capacity: 608 (16)  Entries: 0  Highwater: 0  Bytes: 46
To convert these dates, we need to put either a 19 or 20 in front of the YYMMDD date, depending on the value of the year. Before we can proceed, however, we must once again confirm that there are no invalid dates.
    >base store.dbold
    >get d-sales
    >item deliv-date,date,yymmdd
    >item purch-date,date,yymmdd
    >if $invalid(deliv-date) or $invalid(purch-date)
Once we have fixed the invalid dates, we can start converting. Because there are two date fields in this dateset, we must be careful to add the appropriate century to the correct field. In this example, we assume that years before 1950 are in the 20th century.

We can easily convert each date using the new $stddate function but it is important to note that you will need you redefine the date fields as numeric (display).

     >base store.dbold,1
     Database password [;]?

     >get d-sales
     >set date cutoff 50
     >define deliv-date-z,deliv-date,display
     >define purch-date-z,purch-date,display
     >item deliv-date-z,date,yymmdd
     >item purch-date-z,date,yymmdd
     >ext cust-account
     >ext $stddate(deliv-date-z)
     >ext product-no, product-price
     >ext $stddate(purch-date-z)
     >ext sales-qty / sales-total
     >put d-sales,store.db,1
     Database password [;]?
This converts two dates from an X6 to an X8 format.

How Do I Convert an X6 MMDDYY Date to an X6 YYMMDD Date?

The following Suprtool task shows how we convert a date in a self-describing file from a MMDDYY to a YYMMDD format. Consider the following self-describing file with the deliv-date and purch-date fields:

       File: SALES04.DATA.ACCOUNT   (SD Version B.00.00)
          Entry:                     Offset
             CUST-ACCOUNT         Z8      1
             DELIV-DATE           X6      9       <<MMDDYY>>
             PRODUCT-NO           Z8     15
             PRODUCT-PRICE        I2     23
             PURCH-DATE           X6     27       <<MMDDYY>>
             SALES-QTY            I1     33
             SALES-TAX            I2     35
             SALES-TOTAL          I2     39
       Limit: 115  EOF: 15  Entry Length: 42  Blocking: 97
We want to convert these two dates to a data format of YYMMDD before adding a century in front of the year. This can be accomplished easily by defining each component in the date and extracting the components in the new order.
     >in sales04
     >def deliv-date-mm,deliv-date[1],2
     >def deliv-date-dd,deliv-date[3],2
     >def deliv-date-yy,deliv-date[5],2
     >def purch-date-mm,purch-date[1],2
     >def purch-date-dd,purch-date[3],2
     >def purch-date-yy,purch-date[5],2
     >ext cust-account
     >ext deliv-date-yy
     >ext deliv-date-mm
     >ext deliv-date-dd
     >ext product-no / product-price
     >ext purch-date-yy
     >ext purch-date-mm
     >ext purch-date-dd
     >ext sales-qty / sales-total
     >out sales05,link
We now have a file with the dates in YYMMDD order, but the self-describing information shows three separate fields:
      File: SALES05.DATE.ACCOUNT     (SD Version B.00.00)
         Entry:                     Offset
            CUST-ACCOUNT         Z8      1
            DELIV-DATE-YY        X2      9
            DELIV-DATE-MM        X2     11
            DELIV-DATE-DD        X2     13
            PRODUCT-NO           Z8     15
            PRODUCT-PRICE        I2     23
            PURCH-DATE-YY        X2     27
            PURCH-DATE-MM        X2     29
            PURCH-DATE-DD        X2     31
            SALES-QTY            I1     33
            SALES-TAX            I2     35
            SALES-TOTAL          I2     39
      Limit: 115  EOF: 15  Entry Length: 42  Blocking: 97
We can combine these fields into one field with another Extract task:
      >in sales05
      >def deliv-date,9,6,byte
      >def purch-date,27,6,byte
      >item deliv-date,date,yymmdd
      >item purch-date,date,yymmdd
      >ext cust-account
      >ext deliv-date
      >ext product-no
      >ext product-price
      >ext purch-date
      >ext sales-qty / sales-total
      >out sales06,link
      IN=15, OUT=15.  CPU-Sec=1.  Wall-Sec=1.
The result is a file that looks like this:
      File: SALES06.DATA.ACCOUNT   (SD Version B.00.00)
         Entry:                     Offset
             CUST-ACCOUNT         Z8      1
             DELIV-DATE           X6      9       <<YYMMDD>>
             PRODUCT-NO           Z8     15
             PRODUCT-PRICE        I2     23
             PURCH-DATE           X6     27       <<YYMMDD>>
             SALES-QTY            I1     33
             SALES-TAX            I2     35
             SALES-TOTAL          I2     39
       Limit: 115  EOF: 15  Entry Length: 42  Blocking: 97
Now we can add the century to these fields as described above.

....Back to the Suprtool Q&A Page