| Topic
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Time keeping database (tkdb)
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IANA time zone database (tzdb)
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| Terminology
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Exactly one term for one kind of object
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- Terms are used interchangeably (region = zone)
- Terms are used ambiguously (zone for IANA zones and real world zones)
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| Geography - Sector
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Smallest territorial unit is named "sector"
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Smallest territorial unit is named "zone"
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| Geography - Sector
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For any point in time, except for war time, the legal time in all territory of a sector has been the same.
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For any point in time after 1970-01-01T00:00:00 clocks in a IANA zone have agreed.
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| Geography - Sector
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The sectors cover the whole surface of the earth
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Some areas are not covered, e.g. no IANA zone exists the ISO 3166 country "Bouvet Island"
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| Geography - Sector
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Each sector has exactly one sector ID.
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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)
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| Geography - Sector
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A sector ID only contains alphanumeric characters, letters upper case. REGEX: /[A-Z0-9]{1,}/ (Note: further restriction likely)
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A zone ID contains ASCII letters and / and can contain -._
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| Geography - Sector
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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.
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- 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
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| Geography - Sector
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Relations between deprecated sectors and the sectors that have been created out of them are published.
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No split history is explicitly published.
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| Geography - Country
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ISO 3166-1 alpha-3 codes for countries.
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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.
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| Geography - Country
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Support for former countries at least back to 1946-01-01, the first full year where the UN existed.
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No support for former countries. No way to get data for ISO 3166 alpha-2 code DD (East Germany)
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| Geography - Country
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At any point in time (at least after 1946-01-01) the land surface is associated to a country.
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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.
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| Geography
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At any point in time a sector is located in only one country.
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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.
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| Geography
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Publish relations between sectors and IANA zones at least for some IANA releases.
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| Other
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Record all legal time
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- no time for Bouvet Island, while Norwegian government has defined it,
- limited support for pre-1970 data
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| Other
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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.
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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.
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| Data format
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Publication in
- SQL (?)
- as xCal/iCal (?)
- IANA specific format, as far as that format supports the features of the tkdb.
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Publication in IANA specific format.
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