Database Reference
In-Depth Information
As a practical matter, most systems today probably don't delete users
outright but put them in the
deleted
state instead. This does not change
our design.
The danger here is of unknown friends. If you don't perform the
<user_id>
deletion correctly, you might have friends that were deleted and which
might show up as unknown.
With this preparatory work, we are ready for the problem of the day, also
called
soup du jour
in French. If you got this joke, then what does
soup du
siecle
mean? With this out of the way, we are ready to start with the promised
video site based on a real-world problem.
Applying the many-to-many relationship
techniques for a video site
The problem of a many-to-many relationship is a common one, in HBase and
in Cassandra as well as in many NoSQL databases. It is true that some NoSQL
databases give you limited secondary indices, but this is as far as it goes—they
impose a performance penalty and are not generic. So, you are on your own.
However, we have already dealt with this in the example before, and we know
that we need to introduce additional tables to implement this functionality for us.
