On Wed, Apr 04, 2012 at 12:30:48PM +0000, Black, Michael (IS) scratched on the
wall:
> However....the DB file is portable across big/little endian and 32/64 bit.
Yes. As I said, SQLite will automatically convert values when the
file and platform endian don't match.
> I guess SQLite uses the endianess of the database file over the architecture?
Yes. The endianess of the file is set on creation, and cannot be
changed (without a full VACUUM). By default, the encoding defaults
to the host platform's native endian. You can use the "encoding"
PRAGMA to over-ride this, however.
-j
> ________________________________
> From: sqlite-users-boun...@sqlite.org [sqlite-users-boun...@sqlite.org] on
> behalf of Jay A. Kreibich [j...@kreibi.ch]
> Sent: Wednesday, April 04, 2012 7:26 AM
> To: General Discussion of SQLite Database
> Subject: EXT :Re: [sqlite] Hashing 2 SQLite db files with the same data
>
> On Wed, Apr 04, 2012 at 11:15:10AM +1000, Webdude scratched on the wall:
>
> > But the same SQLite version, using the same schema, setup with the
> > same PRAGMA's, creating a db with the same data and in the same
> > order, and despite hardware / HDD / OS, should still produce the
> > same file byte-for byte ?
>
> No. (And you thought this was going to be easy, didn't you?)
>
> By default, the database file uses the same endian as the platform
> used to create the database file. On platforms where the endian is
> different from the file, there is an automatic conversion. This
> means the *information* in the database can be the exact same, but
> the *file* can still be different.
>
> IIRC, the endian only applies to UTF-16 encoded strings, however.
>
>
> And yes... there is a PRAGMA to set this ("encoding"). So, if "setup
> with the same PRAGMAs" is absolutely true across dozens of PRAGMAs, the
> files should be the same.
>
> If you want to do this, however, you're going to need to set a whole
> boat-load of PRAGMAs on both platforms, and make sure you get them
> just right... and re-examine the list every time you upgrade SQLite.
>
> -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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--
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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