Date Variance Type
Use Date Variance to output randomized dates.
Set the options to alter input dates based on a date variance type (set number of days, months, years, or within a set range).
When using the fixed days, months, and years options, the application generates an internal calculation based on the variance number. For example, if you have an input value of "May 27, 2005" and select Fixed Months and a variance of three, then the calculated minimum and maximum dates are Feb 27, 2005 and Aug 27, 2005. If you have set a user-defined minimum date of Apr 1, 2005 (within the calculated minimum value), and a user-defined maximum date of Dec 31, 2005 (outside the calculated maximum value), then the new valid range is April 1, 2005 (the user-defined minimum) through Aug 27, 2005 (the internally calculated maximum value).
| Option | Description |
|---|---|
| Variance Type |
Define how you want to vary a date. Fixed days: Varies the date by a fixed number of days that occur before or after the input date. Fixed months: Varies the date by a fixed number of months that occur before or after the input month. Fixed years: Varies the date by a fixed number of years that occur before or after the input year. Range: Varies the date within the user-defined minimum and maximum dates that you set. You must set the Minimum and Maximum date values. |
| Variance | Required for the variance types (days, months, years). Determines the number of days, months, or years by which to randomize the input. Enter a value greater than zero. |
| Minimum date | Required for range variance, and optional for fixed date variance types. Enter a date, or select a value by clicking on the calendar icon. The minimum acceptable date value is Sep 14, 1752. |
| Maximum date | Required for range variance, and optional for fixed date variance types. Enter a date, or select a value by clicking on the calendar icon. The maximum acceptable date value is Dec 31, 9999. |
Example
The following table shows several examples for one date value in a database: May 27, 1995. The examples help to illustrate how the date is calculated internally, and how it is output when the user-defined minimum and maximum values are used together.
| Variance Type | Internally calculated date | Output value is within this range | Notes |
|---|---|---|---|
|
Fixed Days Variance: 10 Minimum date: <not set> Maximum date: <not set> |
Min date: May 17, 1995 Max date: Jun 6, 1995 |
Min date: May 17, 1995 Max date: Jun 6, 1995 |
The output uses the internally calculated dates, because the user-defined dates are not specified. |
|
Fixed Days Variance: 100 Minimum date: Mar 1, 1995 Maximum date: Aug 31, 1995 |
Min date: Feb 9, 1995 Max date: Sep 4, 1995 |
Min date: Mar 1, 1995 Max date: Aug 31, 1995 |
The user-defined minimum and maximum dates are within the calculated minimum and maximum dates. Therefore, the user-defined dates are used. |
|
Fixed Months Variance: 6 Min date: Jan 1, 1995 Max date: Dec 31, 1995 |
Min date: Nov 27, 1994 Max date: Nov 27, 1995 |
Min date: Jan 1, 1995 Max date: Nov 27, 1995 |
The user-defined minimum date is within the calculated variance, and is the value used for output. The maximum user-defined date is outside of the calculated variance. Therefore, the maximum calculated date is used. |
|
Fixed Years Variance: 15 Min date: Jan 1, 1965 Max date: Dec 31, 2015 |
Min date: May 27, 1980 Max date: May 27, 2010 |
Min date: May 27, 1980 Max date: May 27, 2010 |
Both of the user-defined minimum and maximum dates are outside of the calculated variance. Therefore the calculated date is used. |
|
Range Min date: Jan 1, 1965 Max date: Dec 31, 2015 |
n/a |
Min date: Jan 1, 1965 Max date: Dec 31, 2015 |
Because there is no variance for range, only the user-defined minimum and maximum values are used. |
