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* multi table import from 1 denormalized source table
@ 2010-11-16 05:57 Andreas <maps.on@gmx.net>
2010-11-16 08:21 ` Re: multi table import from 1 denormalized source table Jasen Betts <jasen@xnet.co.nz>
0 siblings, 1 reply; 2+ messages in thread
From: Andreas @ 2010-11-16 05:57 UTC (permalink / raw)
To: pgsql-sql
Hi,
I frequently get tables from spreadsheets to import into the DB.
Usually it looks like this:
A1, A2, A3, A4, B1, B2, B3, with optional C1, C2, D1, D2, ...
and there is a 1:n relation between A and B.
If provieded the C would be 1:1 to A and D 1:1 to B.
Up until now I let a VBA script order the source table by A, then scan
the table line by line and create a new entry in the target table A* and
fetch its serial ID everytime the script figures that A changed.
With this IDa create 1 C* and as many B*s until A changes again ... and
of course fetch IDb to attach the D* records with a foreign key column.
Now I'm trying to get away w/o the VBA stuff.
Is there a clever way to split such denormalized sources while still
obtaining the needed IDs to connect everything?
^ permalink raw reply [nested|flat] 2+ messages in thread
* Re: multi table import from 1 denormalized source table
2010-11-16 05:57 multi table import from 1 denormalized source table Andreas <maps.on@gmx.net>
@ 2010-11-16 08:21 ` Jasen Betts <jasen@xnet.co.nz>
0 siblings, 0 replies; 2+ messages in thread
From: Jasen Betts @ 2010-11-16 08:21 UTC (permalink / raw)
To: pgsql-sql
On 2010-11-16, Andreas <maps.on@gmx.net> wrote:
> Hi,
>
> I frequently get tables from spreadsheets to import into the DB.
>
> Usually it looks like this:
> A1, A2, A3, A4, B1, B2, B3, with optional C1, C2, D1, D2, ...
>
> and there is a 1:n relation between A and B.
> If provieded the C would be 1:1 to A and D 1:1 to B.
>
> Up until now I let a VBA script order the source table by A, then scan
> the table line by line and create a new entry in the target table A* and
> fetch its serial ID everytime the script figures that A changed.
> With this IDa create 1 C* and as many B*s until A changes again ... and
> of course fetch IDb to attach the D* records with a foreign key column.
>
> Now I'm trying to get away w/o the VBA stuff.
>
> Is there a clever way to split such denormalized sources while still
> obtaining the needed IDs to connect everything?
create a temporary table and put the IDS in there.
then do a select distinct to populate table B,
do an update from to put the IDs from B into the temp table
then do a select to populate table A
etc...
--
⚂⚃ 100% natural
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2010-11-16 05:57 multi table import from 1 denormalized source table Andreas <maps.on@gmx.net>
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