May be there is a simple way depending of what means 'combine all the
data'. If that means just _see_ all that data (without the oportunity to
manipulate), there could be defined a VIEW which does a compound SELECT like
CREATE VIEW combined_all as
SELECT ... from db1.T1
UNION SELECT ... from db2.T1
UNION SELECT ... from db3.T1
...
Then it would not be necessary to insert the data from some databases
into another 'from time to time', but you would have all the data 'just
when you need it'.
For details see http://www.sqlite.org/lang_select.html#compound
Ulrich
Am 10.11.2013 18:49, schrieb Dave Wellman:
Hi,
I'm looking at a use case for SQLITE within one of our applications. One
potential scenario would be for multiple, asynchronous processes to build
their own database. Each one would be populating a different table. At some
point it would be 'really useful' to combine all the data into a single
SQLITE database. We'd still be using multiple tables.
Obviously our application can open multiple databases, select all rows from
T1 in one database and insert them into T1 in another database and continue
doing that until we're complete. I can't see any reason why that shouldn't
technically work and it will probably be fast enough from a performance
perspective.
Is there a 'smart' way of doing this using built-in functaionality of
sqlite? I looked for a 'merge databases' command or something similar but
couldn't find anything.
Ah! I may have just found the answer. If I've got databases db1 and db2
attached, can I use something like 'insert into db1.t1 select * from
db2.t1;' (assuming that the 't1' definitions are the same !)?
Cheers,
Dave
Ward Analytics Ltd - information in motion
Tel: +44 (0) 118 9740191
Fax: +44 (0) 118 9740192
www: <http://www.ward-analytics.com> http://www.ward-analytics.com
Registered office address: The Oriel, Sydenham Road, Guildford, Surrey,
United Kingdom, GU1 3SR
Registered company number: 3917021 Registered in England and Wales.
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Ulrich Goebel
Paracelsusstr. 120, 53177 Bonn
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