Date fields

A Date field contains a date. A Date field has all the usual field properties, which are described in "Field properties". There are some additional properties.

Select the Relative property to indicate that this date is not fixed. A relative date is a date that is not bound to any time zone. For example, the beginning of the new year in 2011 was January 1, 2011 00:00. That does not represent a fixed point in time, rather it represents a particular point of time in the context of a time zone.

A benefit of a relative date is that an administrator can define it and reuse it many times. For example, an administrator defines a calendar named US Holiday to contain New Year's Day, President's Day, Independence Day, and other standard holiday observances. The administrator can then use the US Holiday calendar for resources in any of the time zones covered by the US and know that at runtime a relative time is used in the context of the resource and its time zone.

The Default Value property is used to specify a fixed or relative initial value for the field. To specify that the initial value of the field should be relative to the current date, select the radio button labeled Current Date.

If you leave the value of zero, then the default value is the current date. If you put in a value greater than zero, then the default value is that many days before or after the current date. What determines whether it is a number of days before or after the current date is whether the value selected in the drop-down list is + or -.

To specify that the initial value should be a fixed date, select the lower radio button and enter a date into the field next to it.

The Validation property is used to specify what validation should be applied to values people enter for the field in a user interface. Only one value is supported for this property: Valid Date.

The Formula Type property is visible only if the Formula check box is checked. If the Formula check box is checked, it means that the value of the field will be determined by a formula and the field is always read only. The details of how to specify a formula are described in Formulas.

The value in a Date field is stored in the database in milliseconds and contains both the date and the time. Before you perform duration calculations with Date fields, you must strip out the time portion with the DateFromDateTime function. The DateFromDateTime function returns "0:00" (GMT midnight) in the time portion.