Lifespan

READER: There’s a special type of span called a “connection”.

If you think of all the people, places, organisations, bands and things as “nouns”, then the connections are the “verbs”.

They also exist in time.

You mean like…

• noun - verb - noun?
• John Lennon - lived in - Liverpool

?

Yeah.

And there are different types of connection, right?

Yep.

Remember the Darwin example?

Well, there we had “education” and “residence” connection spans.

In the case of a band, there are other connections, like:

• membership (between the band and people)
• created (between bands and albums)
• contains (between albums and tracks)

…and so on.

And connections are themselves just types of span?

Exactly.

So a person will only have been a member of a band for some of their life, just like they’ve lived somewhere or worked somewhere or studied somewhere for a period of time.

• [John Lennon - lived in - Liverpool] started on YYYY-MM-DD and ended on YYYY-MM-DD
• [John Lennon - member of - The Beatles] started on YYYY-MM-DD and ended on YYYY-MM-DD

Everything is a span.

But some connections between things don’t have dates… they’re just… true… right?

Yes, you can think of some connections as being “timeless”, in that they show relationships between things that are defined by their context.

So a track in an album is just always part of the album, released at the same time as that album.

You mean like…

• OK Computer - contains - Paranoid Android

?

Exactly. But something like this - a track - can have a story before it was recorded, and afterwards… if we wanted it to.

What about dates that aren’t exact?

I noticed that the blue plaques have just the year, but other things are full day/month/year

Good catch.

Dates in Lifespan are stored at different precision levels, so year and month and day are separate.

This means we can say YYYY or YYYY-MM and so on.

This translates as something having started or ended “some time in 2012” or “in May 1983” if we need to.

Got it.

But I have a query about queries.