Time database

Mailing list

• http://groups.yahoo.com/groups/tk-db

Desired features

Topic	Time keeping database (tkdb)	IANA time zone database (tzdb)
Terminology	Exactly one term for one kind of object	Terms are used interchangeably (region = zone) Terms are used ambiguously (zone for IANA zones and real world zones)
Geography	Smallest territorial unit is named "sector"	Smallest territorial unit is named "zone"
Geography	For any point in time, except for war time, the legal time in all territory of a sector has been the same.	For any point in time after 1970-01-01T00:00:00 clocks in a IANA zone have agreed.
Geography	The sectors cover the whole surface of the earth	Some areas are not covered, e.g. no IANA zone exists the ISO 3166 country "Bouvet Island"
Geography	Each sector has exactly one sector ID.	Some zones have multiple IDs via links. These links can represent former IDs of the zone due to spelling change for the reference location represent former IDs of the zone due to reference location change (Tel Aviv -> Jerusalem) represent IDs of former zones (Vaduz links to Zurich)
Geography	ISO 3166-1 alpha-3 codes for countries.	ISO 3166-1 alpha-2 codes for countries. Some of the codes have been re-assigned, e.g. CS can refer to Czechoslovakia or Serbia and Montenegro.
Geography	Support for former countries at least back to 1946-01-01, the first full year where the UN existed.	No support for former countries. No way to get data for ISO 3166 alpha-2 code DD (East Germany)
Geography	At any point in time (at least after 1946-01-01) the land surface is associated to a country.	Some areas are not associated to a country, e.g. the land of the ISO 3166 country "Bouvet Island" is not associated to any country.
Geography	At any point in time a sector is located in only one country.	Zones can be located in different former countries, e.g. Europe/Berlin is located in East Germany (DD) and West Germany (DE) prior to 1990.
Geography	A sector ID only contains alphanumeric characters, not case sensitive. (Note: further restriction likely)	A zone ID contains ASCII letters and / and can contain -._
Geography	New sectors are created only by splitting and deprecating old sectors, so a user can know if an assignment of an ID to an object needs a check for correctness.	User can link an object to a tzid, but get's no notification if later the object is located in another zone having a different tzid Different locations are linked, e.g. Vaduz points to Zurich, Tel Aviv to Jerusalem
Geography	Relations between deprecated sectors and the sectors that have been created out of them are published.	No split history is explicitly published.
Geography	Publish relations between sectors and IANA zones at least for some IANA releases.
Other	Record all legal time	no time for Bouvet Island, while Norwegian government has defined it, limited support for pre-1970 data
Other	For any point in time, for any country, a time zone acronym used for a sector that is located in that country refers to exactly one offset from a base time.	For some points in time during DST observance in Australia, the acronyms EST and CST for time records in Australia can refer to different offsets from UTC, depending on whether a zone observes DST or not. That means for a given point in time during summer the offset from UTC and therefore UTC itself cannot be derived from the local time representation.
Data format	Publication in SQL (?) as xCal/iCal (?) IANA specific format, as far as that format supports the features of the tkdb.	Publication in IANA specific format.