Re: [Shotwell] Map Widget Update

Sorry, meant to -list on the previous message (but now since other
people may have interesting things to add).

We'd still need schema versioning, though we could possibly extend
the time between schema changes.  They'd still be necessary in the
case of destructive schema changes (i.e. drop column).  I'm thinking
something along the lines as:

That would mean getting rid of the explicit schema version number, no?

CREATE VIEW schema_20 AS
  all the columns you need to operate in schema 20

Then verify_database doesn't need to check for equality, it just
needs to check that the view that it needs to operate exists. 
upgrade_database would be on the hook to alter the underlying table
and create the new view for a given version.  In the event the change
was destructive probably delete the old views.  Per a commend in
Db.vala:~135 it looks like we never truly drop columns.  We do stop
writing to them, so they become stale, which means previous versions
can no longer trust the contents of those columns.  It seems to me
the safer route would be to drop the column so that an older version
of the software doesn't read out data which is not populated by a
newer version.  The comment is not untruthful about dropping columns
being difficult in sqlite (here's a good example of how it seems to
be done:  Since
we'd only be dropping columns when we know we're breaking backwards
compatibility we wouldn't need to remake old views to point to the
new incarnation of the table (since versions of shotwell which would
need those views would no longer work anyways).

Does any of that make sense?  Anyone hanging out on irc these days?
Have to think about it. Dropping columns in SQLite is slightly
annoying, yes. I think I used something similar in Rygel to do this.

I'm (phako) usually on during evenings (CET)

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