On Thu, Sep 03, 2009 at 03:47:50PM -0400, Wilson, Ronald scratched on the wall:
> > You can convert a V1 database into a V4 database by opening it, > > setting the legacy PRAGMA to false, and the VACUUMing the database. > If this is true, the documentation doesn't even hint at the feature: > "This flag only affects newly created databases. It has no effect on > databases that already exist." I agree that the docs are a bit light on this point. I would have never guessed about the VACUUM thing, if it wasn't for the fact I ran across this line in the 3.2.8 to 3.3.0 section of <http://www.sqlite.org/formatchng.html>: "Once a database file is created, its format is fixed. So a database file created by SQLite 3.2.8 and merely modified by version 3.3.0 or later will retain the old format. Except, the VACUUM command recreates the database so running VACUUM on 3.3.0 or later will change the file format to the latest edition." That is, the way VACUUM essentially works is that it copies everything to a temp database, creates a brand-new-from-scratch database, and copies everything back. When it creates the new database, that database takes on the current defaults. If you stop and think about it, it isn't that big of a surprise. You can use VACUUM to change the page size and a bunch of other "fixed" parameters. However, it might be nice if the docs were a bit more forthcoming about this point. > One way to test it would be to try opening an up-converted database in a > version previous to 3.3.0, which I don't have handy. The other way (which is what I did) is to just dump the first ~50 bytes of the file and see what version is set. See "44..47" here: <http://www.sqlite.org/fileformat.html#database_header>. It would be kind of nice if there was some PRAGMA command that dumped all this type of info for the current "main" database. I don't remember if sqlite3_analyzer does or not. -j -- Jay A. Kreibich < J A Y @ K R E I B I.C H > "Our opponent is an alien starship packed with atomic bombs. We have a protractor." "I'll go home and see if I can scrounge up a ruler and a piece of string." --from Anathem by Neal Stephenson _______________________________________________ sqlite-users mailing list sqlite-users@sqlite.org http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
