Oracle8i Time Series User's Guide
Release 8.1.5

A67294-01

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Glossary

anchor date

The date to be used for establishing the start of a pattern and (based on the pattern) which timestamps are to be included in and excluded from the calendar. For example, consider a pattern of `0,1,1,1,1,1,0' over a day frequency defines a calendar over all weekdays. If an anchor date of 01-Jun-1997 (or any Sunday) is specified, then the 7-day pattern begins each Sunday; and Sunday and Saturday (0) are excluded from the calendar, while Monday through Friday (1) are included in the calendar.

calendar

A data structure that maps human-meaningful time values to underlying machine representations of time. The calendar definition includes a frequency and a pattern, and optionally exceptions and date boundaries (upper and lower).

exception

A timestamp that does not conform to the calendar pattern but that is significant for the calendar definition. There are two kinds of exceptions: off-exceptions and on-exceptions. (See the glossary definitions for each.)

frequency

The granularity of the calendar representation. The supported frequencies are second, minute, hour, day, week, 10-day, semi-monthly, month, quarter, semi-annual, and year.

group

See time series group.

irregular time series

A time series that does not have an associated calendar. Often, irregular time series are data-driven, where unpredictable bursts of data arrive at unspecified points in time or most timestamps cannot be characterized by a repeating pattern. However, an irregular time series can be used with predictable data where it is simply not necessary to deal with a calendar.

off-exception

An exception to the non-zero bits in the pattern, and thus is a timestamp to be excluded from the calendar. For example, to ensure that Wednesday, 25-Dec-1996, is excluded from the calendar when Wednesdays normally are included, define that date as an off-exception.

on-exception

An exception to the zero (0) bits in the pattern, and thus is a timestamp to be included in the calendar. For example, to ensure that Saturday, 28-Jun-1997, is included in the calendar when Saturdays are excluded, define that date as an on-exception.

pattern

The repeating pattern of frequencies and an anchor date that identifies a valid timestamp for the first element in the pattern. For example, if the frequency is set to day, the pattern can define which days of the week are included in the calendar.

pattern anchor date

See anchor date.

precision

The degree of exactness to which a timestamp needs to be specified. Each frequency has an associated precision. Oracle8i Time Series functions require that input timestamps be of the precision of the frequency associated with the calendar. A timestamp that is not consistent with the frequency is said to be imprecise.

regular time series

A time series that has an associated calendar. In a regular time series, data arrives predictably at predefined intervals. For example, daily summaries of stock market data form regular time series, and such time series might include the set of trade volumes and opening, high, low, and closing prices for stock XYZ for the year 1997.

time series

A set of timestamped data entries. Each time series consists of an identifier (such as stock ticker ACME), and multiple timestamp-value pairs (such as all trading days and the closing price for ACME on each trading day).

time series group

The schema objects for a time series. The time series group is created by administrative tools procedures, starting with a call to Begin_Create_TS_Group and ending with a call to End_Create_TS_Group.




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