-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

On 23/02/12 23:02, Steinar Midtskogen wrote:
> I know that xColumn will only get called for these columns.

As Dan said there isn't a direct way of knowing.  There is a reasonably
convenient workaround of having multiple virtual tables with different
subsets of the columns but all returning the same underlying data.

Something else to look at are hidden columns.  See section 2.1.1 in
http://www.sqlite.org/vtab.html

With that you can make the "cheap" columns regular and the expensive ones
hidden so that the SQL query explicitly has to ask for them.  In your vtab
implementation you can always start out by only getting the cheap columns
until xColumn tells you that one of the hidden/expensive ones is needed
and then go off and redo the underlying query.

Roger
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.11 (GNU/Linux)

iEYEARECAAYFAk9HUG4ACgkQmOOfHg372QSCUACfTFu4145atVIHa716iAkF6slL
XuQAoL2gx0IR3xnMmVBcJYRAXJA+AAhw
=ejgc
-----END PGP SIGNATURE-----
_______________________________________________
sqlite-users mailing list
sqlite-users@sqlite.org
http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users

Reply via email to