To: pgsql-sql@postgresql.org
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From: Jasen Betts <jasen@xnet.co.nz>
Newsgroups: gmane.comp.db.postgresql.sql
Subject: Re: multi table import from 1 denormalized source table
Date: 16 Nov 2010 08:21:46 GMT
Organization: Dis (not Dat) Organisation
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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...


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