UltraLite automatically converts a string into a date when a date value is expected, even if the year is represented in the string by only two digits. In the case of a two-digit date, you need to set the appropriate rollover value.
Choosing an appropriate rollover value typically is determined by:
The use of two-digit dates Otherwise, nearest century conversion isn't applicable. Two-digit years less than the nearest_century value you set are converted to 20yy, while years greater than or equal to the value are converted to 19yy.However, you should always store four-digit dates to avoid issues with incorrect conversions and keep dates unambiguous. See Using unambiguous dates and times.
Consolidated database compatibility For example, the historical SQL Anywhere behavior is to add 1900 to the year. Adaptive Server Enterprise behavior is to use the nearest century, so for any year where value yy is less than 50, the year is set to 20yy.
What the date represents: past event or future event Birth years are typically those that would require a lower rollover value since they occur in the past. So for any year where yy is less than 20, the year should be set to 20yy. However, if the date is used as an expiry date, then having a higher value would be a logical choice, since the date is occurring in the future.
If this option is not set, the default setting of 50 is assumed. Thus, two-digit year strings are understood to refer to years between 1950 and 2049.