Two digits have long been used to represent the year in packed numeric fields used to store dates. As a Y2K fix, some systems added a third digit called a century code to indicate the century to which a two digit year belongs.
The most common century codes use either a leading “0” or a leading “1” to indicate the twentieth century:
| • | When a leading “0” in the packed field is used to represent 1900, any other number, usually “1”, represents 2000. |
0990101 represents January 1, 1999
1000101 represents January 1, 2000
| • | When a leading “1” in the packed field is used to represent 1900, any other number, usually “2”, represents 2000. |
1990101 represents January 1, 1999
2000101 represents January 1, 2000
After using the Data Definition Wizard to define a packed numeric field, you must manually modify the date format as follows:
| 1. | Select Edit from the menu and choose Edit Table Layout. Analyzer displays the Table Layout window. |
| 2. | Under the [Fields/Expressions] tab, in the field list View, double-click the numeric field you want to edit. Analyzer displays the field format options. |
| 3. | Click the Advanced button and select the Date parameter checkbox. |
| 4. | Specify a date format in the Format drop-down list. Then, in the Format text box, add a “0” or a “1” to the beginning of the packed date field format to specify the digit representing the 1900s. |
| • | For example, the format “0YYMMDD” indicates that 0991231 is December 31, 1999. Similarly, “1YYMMDD” indicates that 1991231 is December 31, 1999. |
| 5. | Click [Accept Entry], then click [OK] to save the change. |
You can see the formatted field in the View.