time stamp

A time stamp is a time value that is added to a data item to record, for example, when it was sensed, created, or updated. A time stamp may be a date (28/07/1960), a precise time (1960-07-28 03:00:00.000), or time since a well known start time (e.g. seconds since 1970). Time stamps are often meta-information about the data, in contrast to dates in the main data itself; for example the birth certificate, which records the data of birth of a baby (data content), is often created, validated and time stamped several days after the birth itself. For status data (e.g. temperature) that is not sampled at regular intervals, the exact time at which data value was sensed is often crucial for subsequent analysis.