Hi 2011/5/31 Stephan Beal <sgb...@googlemail.com>
> On Tue, May 31, 2011 at 5:11 PM, Fabio Spadaro <fabiolinos...@gmail.com > >wrote: > > > "Alter table add column" command drop data from table. > > Can you keep the data or should I store the data before the alter and > then > > put > > them in the table? > > > > http://www.sqlite.org/lang_altertable.html > > says: > > "The execution time of the ALTER TABLE command is independent of the amount > of data in the table. The ALTER TABLE command runs as quickly on a table > with 10 million rows as it does on a table with 1 row." > > Implicit in that statement is that ALTER TABLE does not modify/delete any > table data. If it did, the runtime would probably be O(N) or worse, not > O(1) > (as described above). > > -- > ----- stephan beal > http://wanderinghorse.net/home/stephan/ > _______________________________________________ > sqlite-users mailing list > sqlite-users@sqlite.org > http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users > Ok I have been deceived by the anomaly that I found in my application. In practice I have renamed the table (with alter table), I inserted a row and then I inserted a new column (with alter table add column) and to my surprise I saw the empty table. The problem is that my insert is not successful and what you do not understand why try to make the insert taking the old name of the table. To recap: Step 1: alter table pippo rename to fabio -> ok step 2: insert into fabio (field1) values ('1 ') -> ko OperationalError: no such table main.pippo Step 3: alter table add column fabio field2 integer null -> ok result: empty table Question: Why does my insert referring to the old table? use python sqlite vers. 2.5.9 -- Fabio Spadaro www.fabiospadaro.com _______________________________________________ sqlite-users mailing list sqlite-users@sqlite.org http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
