> hjp-pg...@hjp.at wrote:
>
>> Bryn wrote:
>>
>> "isbn" — string
>> values must be unique across the entire set of documents (in other words, it
>> defines the unique business key); values must have this pattern:
>>
>> « ^[0-9]{3}-[0-9]{1}-[0-9]{2}-[0-9]{6}-[0-9]{1}$ »
>
> Completely off-topic, but this regexp doesn't describe ISBNs. In ISBNs the
> three middle subfields are all variable length. The first is a language code
> (there are more than 10 languages in the world), the second identifies the
> publisher (there are more than 100 publishers) and the third the book. For
> example, "Mastering PostgreSQL 9.6" has the ISBN 978-1-78355-535-2.
Yes, I know. Sorry. I should have said that I simply wanted to illustrate a
proof of concept for the notion, viable (only?) when you have incoming JSON
documents with a well-defined schema, that this is idempotent:
JSON → relational → JSON
And it's of note that PostgreSQL has had what you need to do the xform, in each
direction, for a long time.
I simply typed up my "corpus" by hand. It didn’t matter that the ISBN format
was a fairly tale. A book does have an ISBN and (as far as my P.o.C. is
concerned) it's the unique business key. I should have cut out the REGEXP in my
email and said something like "must conform to the specified format". But I was
careless in my proof reading.
Thanks for not mentioning that books have publishers—so that "authors" isn't
the only key that implies a Codd-and-Date many-to-many!
