[Opa] documentation for database functions

N Owen Gunden ogunden at phauna.org
Wed Jan 18 18:41:57 UTC 2012


On Wed, Jan 18, 2012 at 11:24:47AM +0100, Matthieu Guffroy wrote:
>    To return on your first question, (you were asking about how to know if
>    a key is existing).
> 
>    There is a function Db.exists who take a path as parameters and return
>    a boolean.
> 
>    A path is something like this : @/my/path[my_key]  (but could also be
>    @/my/path)

Thanks. I saw Db.exists but did not realize that it would work with a
path which indexes into the intmap like that. Cool!

>    Indeed you could also use the optional get ?/my/path[my_key]
> 
>    but if your goal is not to read the data just checking if exists, if
>    thinks it's less good.

This turns out to be exactly what I was looking for, I just didn't
know it existed. I don't see it on the "database" page of the manual.
Is it documented somewhere?


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