Hi all,
Where can I get an example of xFilter implementation? The issue I am having
here is that when I am trying to execute a "select * from tablex where value=1"
all I get is the last result from the file (336cc2282716::1).
int my_filter( sqlite3_vtab_cursor* pCursor, int idxNum, const char *idxStr,
int argc, sqlite3_value **argv )
{
csv_cursor * cur = (csv_cursor *) pCursor;
csv_vtab * tab = (csv_vtab *) cur->cursor.pVtab;
csvfile_rewind( tab->csv );
csvfile_read( tab->csv ); /* skip first row with column names */
cur->csvpos = csvfile_tell( tab->csv );
csvfile_read( tab->csv ); /* skip first row with column names */
return SQLITE_OK;
}
***first row in the file not important
ed527dc53686::1
336cc2282716::1
41f955b0::0
00225828815a::1
00271368ace9::0
f0def10e9046::0
70b1e68e9e67::0
ed527dc53686::1
336cc2282716::1
When I do "select * from tablex" I get all the results fine. It is only when I
use the where clause is that I get strange results.
Any hints will be greatly appreciated.
-----Original Message-----
From: [email protected] [mailto:[email protected]]
On Behalf Of Jay A. Kreibich
Sent: Friday, February 25, 2011 11:00 PM
To: General Discussion of SQLite Database
Subject: Re: [sqlite] Virtual Table and the xBestIndex
On Fri, Feb 25, 2011 at 09:30:00PM -0500, Dariusz Matkowski scratched on the
wall:
> I am trying to implement a simple virtual table that reads in a file
> with two columns and "::" separator. My question is: is it necessary
> to implement xBestIndex to run a simple where clause queries?
You must implement a xBestIndex() function, but it does not need to
do anything other than return SQLITE_OK. This will result in a full
table scan for each query, but for something like a flat file (where
you cannot easily jump to specific records) that's usually not a
significant limitation.
-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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