A description of the eleven fields in each row of the time zone database.
ID: (Required). Contains the identifying label for the time zone region. A "region" is a longer string used to identify the time zone. An example would be America/Pacific for the Pacific coast time zone in America. Any string can suffice as long as it is unique within the time zone database.
STD Abbreviation: (Required). This contains the abbreviation of the time zone. The STD means Standard Time Zone Designator. This is the familiar PST or EST, and is the standard time when daylight savings is not in effect. Abbreviations should consist only of upper case letters, while the name can be any descriptive string. Lower case abbreviations, if present, are capitalized by the system.
STD Name: The STD means Standard Time Zone Designator. The STD Name is the longer version of the name for standard time. For PST this could be Pacific Standard Time.
DST Abbreviation: This contains the abbreviation of the time zone. The DST Abbreviation is used to label daylight savings time. For example, in the PST time zone, this would be PDT. Abbreviations should consist only of upper case letters while the name may be any descriptive string. Lower case abbreviations, if present, are capitalized by the system. This entry is optional; time zones that do not use daylight savings time do not need the DST abbreviation and name.
DST Name: The DST name is a longer version of the name of the time zone. For PDT this could be Pacific Daylight Savings Time. This entry is optional; time zones that do not use daylight savings time do not need the DST abbreviation and name. Please see below for further discussion of DST entries.
GMT Offset: This is the number of hours added to Greenwich Mean Time to get the local time before any daylight savings adjustments are made. Some examples are: America/Pacific offset: -8:00 hours, Africa/Cairo offset: +2:00 hours.
DST Adjustment: The amount of time added to the local time when daylight savings is in effect. This format must follow the length-of-time format described above. For the United States this is typically "1:00"
DST Start Date Rule: Describes the day of the year in which the transition to daylight savings time takes place. See Date Rules" above for specific formatting rules.
Start Time: The time of day to begin daylight savings time in 24 hour time format. The format must follow the length-of-time describe above. For time zones in the United States this is typically "+02:00" meaning daylight savings starts 2 hours past midnight.
DST End Date Rule: Describes the day of the year in which daylight savings time ends and standard time begins again.
End Time: The same as the Start Time, but for the ending date. For the United States this is typically "+02:00".
Daylight savings time is optional. Many time zones do not use daylight savings time. The time zone software insists that daylight savings time either be wholly present or wholly absent. An error message is generated if this is not true. A missing field is indicated by simply using a comma to skip to the next field. Thus, for Japan Standard Time, there is no daylight savings time and the entry would be similar to:
ID - "Asia/Japan"
STD Abbr - "JST
STD Name - "Japan Standard Time
DST Abbrev - empty
DST Name - empty
GMT Offset - +09:00
DST Adjustment - empty
DST Start Rule - empty
DST Start Time - empty
DST End Date Rule - empty
DST End Time - empty
The Sybase CEP Time Zone Database stores only one set of information about each time zone. This means that when rules (for example, for daylight savings time) are updated, Sybase CEP knows only the current rules. Thus, for example, if in the year 2007 you change the starting date of daylight savings time from "the first Sunday in April" to "the second Sunday in March", then after you update the Sybase CEP time zone database, Sybase CEP will treat the second Sunday in March as the start of daylight savings time, even for years prior to 2007.
The fields in the time zone CSV database are used by the Sybase CEP software to link external time zone names to the proper time calculations. Within the time zone database, the following must be unique within the entire database:
ID.
STD Abbreviation.
DST Abbreviation.
This uniqueness allows users to identify time zones in various ways. The identification applies to both input and output of time zones.
ID maps to TZR, the Time Zone Region. This is output only.
STD abbreviation maps to TZD, the Time Zone Designator. Use in the input or output.
DST abbreviation maps to TZD as well. Use this in input or output.
TZH:TZM displays as time zone hours and minutes from GMT. This is output only. While TZH and TZM are typically displayed together, they may be separated and placed however you desire.
Standard and Daylight savings time abbreviations can be used interchangeably. The Sybase CEP software can, if applicable, modify the time for daylight savings and interpret the appropriate STD or DST abbreviation. As in all date-time format strings, multiple uses of the same format code are illegal on input, but are legal in output formats. Thus the following is illegal because multiple TZD formats are illegal for input:
TO_TIMESTAMP("2002-06-18 PDT13:52:00.123456 PST,
"YYYY-MM-DD TZDHH24:MI:SS.ff TZD");
An output request allows multiple format requests:
TO_STRING(ts, "YYYY-MM-DD TZDTZDTZD", PDT) yields: "2006-06-18 PDTPDTPDT