Time_Expression
Description:
Name Null? Type
------------------------------- -------- ----
TIME_EXPRESSION_ID NOT NULL NUMBER
TIME_SUBTYPE VARCHAR2(13)
Primary Key:
- Time_Expression_ID
There are a number of different ways of expressing the time at which something
was collected. The most precise will be a specific date, perhaps even a
specific time of day. These are stored in the
Clock_Time table as dates (which allows Oracle
to do date arithmetic with them). Indeterminate times, such as
1983 or August are stored as text fields in Period.
The Relevant_Time table contains even more vague time references, such
as late summer, 1968.
The Time_Subtype refers to the different ways the collecting dates are stored:
The Time_Expression_ID field in the table Collecting_Event
relates these two tables.
Last updated: 20 November, 1997 by nfj.