CEM street key
The key SKYDB computes to hold one street identity from the CEM street network of metropolitan Sao Paulo.
This key is generated by SKYDB, not issued by anyone. It is a SHA-256 digest of the street name together with the sorted list of the segment numbers it was built from, cut to its first 24 characters. Twenty-four hexadecimal characters is the length of that cut and nothing more.
The source is the street network published by the Centro de Estudos da Metropole at the University of Sao Paulo, a research center rather than a government register. It covers 342,209 segments across the metropolitan region and carries no municipal authority, so a street appearing in it is not thereby official. The city's own key is the GeoSampa CODLOG.
Because the key covers the list of segments, a new release of the network that splits or joins a street produces a different key for the same street. It identifies an import identity reliably and a street only for as long as the segmentation holds.
A record can hold more than one, since a single SKYDB street may absorb several of these identity groups.