The centre of the postcode unit is derived from the precise coordinates of addresses sharing the same postcode unit in Ordnance Survey's large-scale address database.

In Manchester for example 25,000 people from 14,000 addresses were not enumerated because the address database was two years out of date.

The Organiser II can be considered the first usable PDA in that it combined an electronic diary and searchable address database in a small, portable device.

She could hear Louis tapping on the laptop keys, where he kept the address database.

It could coordinate its own address database with the database of registered voters, set postmark deadlines and devise language prompting voters to affix correct postage.

By including the map references of postcodes in the address database, the postcode can be used to pinpoint a postcode area on a map.

Any application can integrate with the system-wide address database through a set of public APIs provided by Apple.

By "replaceable" I mean that third party developers should be able to create drop-in replacements for services like the address database.

This has led to various services within individual local authorities maintaining separate and incompatible address databases.

Its primary function is to act as a search engine that allows the user to search a central address database by entering search terms.