On Thu, Jul 08, 2010 at 08:23:55AM -0400, Richard Hipp scratched on the wall:
> On Thu, Jul 8, 2010 at 7:10 AM, Richard Hipp <d...@sqlite.org> wrote:
>
> > Though, I will admit, this is confusing, and I was thinking last night
> > about ways we could possibly change it....
>
> Current behavior:
>
> (1) PRAGMA name.journal_mode=MODE; -- set the mode to MODE for database
> "name".
>
> (2) PRAGMA name.journal_mode; -- return current journal mode for database
> "name".
>
> (3) PRAGMA journal_mode=MODE; -- set the mode to MODE for all attached
> databases and also apply MODE to all databases ATTACH-ed in the future.
>
> (4) PRAGMA journal_mode; -- report the most recent setting by (3). Report
> "delete" if there have been no prior occurences of (3).
>
> First Proposed Change:
>
> (1) and (2) are the same.
>
> (3) PRAGMA journal_mode=MODE; -- set the mode to MODE for all attached
> databases. Databases created by subsequent ATTACH use MODE. Existing
> databases added by ATTACH use MODE if and only if doing so does not require
> them to change in or out of WAL mode.
> (4) PRAGMA journal_mode; -- report the most recent setting by (3). Or if
> (3) has never been used, work the same as "PRAGMA main.journal_mode;"
Contexts are generally bad. This is even more true if there might
ever be a way to change the compile time default journal mode to
anything other than "delete." Then there is no way to get the default.
There are a few pragmas that use this general approach... where
getting/setting an unqualified setting changes the default, not
"main". It might be better if all unqualified statements refer
to main, and pragmas like this have a default.journal_mode (get/set)
or all.journal_mode (set) syntax.
> Second Proposed Change:
>
> Remove the WAL mode from "PRAGMA journal_mode". The journal_mode pragma
> only specifies the various rollback journal modes. Enable the WAL using a
> separate pragma such as "PRAGMA wal=ON; PRAGMA wal=OFF;"
>
> Thoughts? Comments?
I like this. I suspect in the future we will have a "PRAGMA
wal_mode" as well, so this makes a bit more sense.
But as an extension, does it make even more sense to have "PRAGMA
wal=[on|off]" or "PRAGMA transaction=[wal|journal]" ?
> Other suggestions?
This has nothing to do with WAL, but it might be nice to expose
the logic that does SQL-type => SQLite-affinity mappings
(i.e. sqlite3AffinityType()):
int sqlite3_get_affinity( const char *type );
Takes a string that contains an SQL type. Returns one of:
SQLITE_AFF_TEXT, SQLITE_AFF_NONE, SQLITE_AFF_NUMERIC,
SQLITE_AFF_INTEGER, SQLITE_AFF_REAL.
-j
--
Jay A. Kreibich < J A Y @ K R E I B I.C H >
"Intelligence is like underwear: it is important that you have it,
but showing it to the wrong people has the tendency to make them
feel uncomfortable." -- Angela Johnson
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