Moving to full field expansion

Using the millennium language extensions, you can move gradually toward a solution that fully expands the date field.

About this task

Do the following steps:

Procedure

  1. Apply the century window solution, and use this solution until you have the resources to implement a more permanent solution.
  2. Apply the internal bridging solution. This way you can use expanded dates in your programs while your files continue to hold dates in two-digit-year form. You can progress more easily to a full-field-expansion solution because there will be no further changes to the logic in the main body of the programs.
  3. Change the file layouts and database definitions to use four-digit-year dates.
  4. Change your COBOL copybooks to reflect these four-digit-year date fields.
  5. Run a utility program (or special-purpose COBOL program) to copy files from the old format to the new format.
  6. Recompile your programs and do regression testing and date testing.

Results

After you have completed the first two steps, you can repeat the remaining steps any number of times. You do not need to change every date field in every file at the same time. Using this method, you can select files for progressive conversion based on criteria such as business needs or interfaces with other applications.

When you use this method, you need to write special-purpose programs to convert your files to expanded-date form.

Example: converting files to expanded date form