Hi Richard Thanks for the quick response!
D. Richard Hipp wrote: > On Sep 10, 2008, at 2:09 PM, Mohit Sindhwani wrote: > >> >> I've been using SQLite3 for a while though to be honest, it's been >> more >> of a data store rather than a dynamic database in my applications this >> far. I'm now starting on something where my needs are as such: >> * Store 70,000 records in one table in the database >> * Based on a list from the user, extract up to 3,000 records from the >> table (1 common field) >> * Use the 3,000 records for calculations, etc. >> * Support concurrency of up to 10 such operations >> > > > Your description implies that database is read-only. Is this > correct? If so, then concurrency will not be a problem since SQLite > supports as many simultaneous readers as you like. Only writers need > to be serialized. > > If you create a TEMP table to hold the 3000 selected records then do: > > INSERT INTO temptab SELECT * FROM maintab WHERE ...; > > You can then do your computations on the temporary table without even > interfering with writers on the main table. > The main table is read-only - there will be no writes to the main table. The TEMP tables (one for each concurrent access) would involve writing since I will somehow need to insert the 3000 records from the user into the TEMP table and also the joined results. If I use temp tables, wouldn't the creation of one block the rest from writing at the same time? Finally, on a related but different note, what is the limit for a SQL statement? I'm receiving 3000 IDs from the user and what I really need to do is: INSERT INTO temptab SELECT * FROM maintab WHERE id IN (1, 3, 89, 22, 324, ..); With 3000 records (actually each ID is 6 digits), this would lead to a SQL query that runs into 24KBytes or so! I'm sure I'm missing something. (By the way, this would all be in a Windows application using SQLite embedded into the application). Thanks again, Mohit. _______________________________________________ sqlite-users mailing list sqlite-users@sqlite.org http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
