In the real world, events begin and end on exact dates and at exact times. In a chronology, not all this information might be known for a particular event. Indeed, in some chronologies, the administrator might decide not to collect some of this information at all.

Chronolator always ensures that the Start Date of event is specified, but the Start Time, End Date and End Time are often missing. How does it deal with such events?

Assumptions

Individual events

When information about the exact start or end of an event is missing, Chronolator makes the following assumptions so that it can be processed.

• if Start Time is missing, it is assumed to be midnight (00:00)
• if End Date is missing, it is assumed to be the same as Start Date
• if End Time is missing, it is assumed to be the same as Start Time

Durations

Sometimes the elapsed time between two instants needs to be calculated; for example, the interval between two events, or between the start and end of a single event. Chronolator assumes that any information missing in the later instant is the same as that of the earlier one.

Assumed information is never displayed

Whatever assumptions Chronolator might make about missing information, it will never display those assumptions explicitly. For example:

• an event which Chronolator assumes to start at midnight, for example, will never include that time in any display
• a duration based upon an assumed time will only include date-based information

Overriding Chronolator's assumptions

Sometimes you might know the order in which events happen even though you do not know their dates and time exactly. In these circumstances you can use a Sequence column to ensure that Chronolator sorts events in the order you specify. The Check Tables button can still be used to check that such 'manually' sorted events are in a valid order. For more information about the Sequence column, see Using a Sequence column.