The trick is to have a way to identify the first/current row and use that in
the WHERE clause.
e.g. SELECT ... FROM customers WHERE customer_id >= last_displayed LIMIT
window_size
If your select statement is a complex join without any usable key, you will
have to resort to storing the results
CREATE TEMP TABLE select_results AS SELECT ...
And displaying only those within the current window
SELECT * FROM select_results WHERE rowid >= starting_line LIMIT window_size;
As an optimization, you can populate the temporary table in the background
while displaying the first page of results.
-----Ursprüngliche Nachricht-----
Von: sqlite-users [mailto:[email protected]] Im
Auftrag von Thomas Flemming
Gesendet: Mittwoch, 24. Mai 2017 10:09
An: [email protected]
Betreff: [sqlite] SQLite3.Step fast forward / skipping rows
Hi SQLite Users,
I have a SELECT query, which returns some 100000 records and is displayed in a
scrollable ListView.
When the user scrolls down the list, each new row is loaded with SQLite3.Step().
The problem is, when the user scrolls fast with the scroll-slider, lots of rows
are skipped, but SQLite still needs to load them all with SQLite3.Step until it
reaches the row which is actually needed. This is very slow.
Is there a way to skip all these unnecessary rows? For example going directly
from row 1000 to row 100000 ? I tried SELECT ... OFFSET 100000 but this is also
very slow the more down we go.
Thanks
Tom
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