Time database
Mailing list
Desired features
| Topic | Time keeping database (tkdb) | IANA time zone database (tzdb) |
|---|---|---|
| Terminology | Exactly one term for one kind of object |
|
| Geography - Sector | Smallest territorial unit is named "sector" | Smallest territorial unit is named "zone" |
| Geography - Sector | For any point in time, except for war time, the legal time in all territory of a sector is the same. | For any point in time after 1970-01-01T00:00:00 clocks in a IANA zone have agreed. |
| Geography - Sector | 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 - Sector | Each sector has exactly one SectorID. | Some zones have multiple IDs via links. These links can
|
| Geography - Sector | A SectorID only contains alphanumeric characters, letters upper case. REGEX: /[3-8][A-Z0-9]{1,}/ (Note: further restriction likely) | A zone ID contains ASCII letters and / and can contain -._ |
| Geography - Sector | 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. |
After a split one zone retains the ID of the old zone. That means:
|
| Geography - Sector | Relations between deprecated sectors and the sectors that have been created out of them are published. | No split history is explicitly published. |
| Geography - Country | 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 - Country | 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 - Country | 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 | Publish relations between sectors and IANA zones at least for some IANA releases. | |
| Other | Record all legal time |
|
| 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
|
Publication in IANA specific format. |
Tables
District
All land surface belongs to exactly one district. They allow grouping of sectors by larger geographic regions. Not used:
- 0 - to avoid misreadings as O
- 1 and 2 - to avoid that a 4-digit SectorID could look like a year
| DistrictID | DistrictName | Description |
|---|---|---|
| 3 | Antarctica | |
| 4 | Africa | |
| 5 | America | |
| 6 | Oceania | |
| 7 | Europe | including Soviet Union territory, including Cyprus, Malta, excluding Turkey |
| 8 | Asia |
Country
A country is a political entity. The concept is based on the concept of country in ISO 3166-1.
Sector
A sector
- is located in exactly one district
- has exactly one SectorID
- is not divided by country boundaries since 1946-01-01T00:00:00.
A SectorID:
- conforms to the REGEX: /[3-8][A-Z0-9]{1,}/ (Note: further restriction likely)
- has the DistrictID as the first character
- contains no reference to a country (IANA zone sometimes to, e.g. those for Argentina)
There should be a Private Use Area in the SectorID space, to allow people that like to do different sectorization to create non-clashing SectorIDs.