How to modify city/country data

Not all combinations of cities and countries can be modified or deleted and not any name may be used for a city or country. Country names must be unique, and cities must have a unique name within their country—though the same name may be used for cities in different countries.

Cities must be added to a valid country and have a valid DST zone. To add a city, a TCityData is filled with the data and the server is called to add the information. Likewise, the server can add new country information contained in a TCountryData.

To update or delete a city or country, the session must first obtain the correct TWldID. Capital cities, the home city, home country or default country cannot be deleted. If a country is deleted, its cities are added to the null country. Any attempt to delete a location from the read-only file, will return an error.