On Thu, 08 Dec 2011 08:48:51 +0200, Andreas <maps...@gmx.net> wrote:
Hi,
suppose you need to import a csv with standard ciolums like name,
adress, phone, ... and some additional text columns that need to be
split off into referenced tables.
Those lookup-tables will only be needed for a project with limited life
time so I create a schema that might be called "project_x". There I
create the necessary lookup tables.
The core of the import will be added to the customers table with
unlimited livespan. The customers table has a PKey id which is a serial.
I don't want to add FKey columns into customers for the new
lookup-tables so I create another table in project_x "projectinfos" that
stores those FKeys and another FKey that references customers.id.
First question: Is this a stupid aproach?
It is logical to reduce dependency from the temporary schema to the
customer table which is on the permanent schema.
If not:
How is the easiest way to to find the customer.id of the new customers
so I can insert the projectinfos?
It is easy to select rows not related with another table. One of the
following queries can be used.
Select * from "customers" where id not in (select "customerId" from
"projectinfos")
Select * from "customers" left join "projectinfos" on "customers"."id" =
"projectinfos"."customerId" where "projectinfos"."customerid" is null
Select * from "customers" where not exists (select true from
"projectinfos" where "customers".id = "customerId")
--
Sent via pgsql-sql mailing list (pgsql-sql@postgresql.org)
To make changes to your subscription:
http://www.postgresql.org/mailpref/pgsql-sql
