-----Original Message-----
From: pgsql-sql-ow...@postgresql.org [mailto:pgsql-sql-ow...@postgresql.org] On 
Behalf Of Andreas
Sent: Wednesday, February 15, 2012 8:03 PM
To: pgsql-sql@postgresql.org
Subject: [SQL] need help with import

Hi
I get CSV files to import.
Th structure is like this.
main part, sub part
Could be like this

A, a1
A, a2
A, a3
B, b1
B, b2

The database has a table for main_part and one for sub_part.
The relation needs to be n:m so there is a relation table that holds ( main_id, 
sub_id ).
The 2 primary keys main_part.id and sub_part.id are both serials.

Is there a way to do an import with SQL?

I can read the CSV into a temporary table and I can do a INSERT INTO main_part 
( ... ) SELECT DISTINCT main columns FROM import; as well as a INSERT INTO 
sub_part ( ... ) SELECT sub columns FROM import;

But how would I know what main_id and sub_id to insert into the n:m relation?

At first when I do the import the relation is actually 1:n.

--------------------------------------------

You will need to use the temporary table and perform multiple insert+select.

I do not understand where you are confused.  It would help to provide more 
meaningful sample data and/or the final result you are trying to achieve.  Keep 
in mind any n:m setup requires three tables with the joining table usually 
having some descriptive meaning.  Is time one of your components that you are 
not  showing us?

Dave


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