Re: INSERT INTO relational tables

am Mon, dem 10.12.2007, um 11:42:04 +0100 mailte Stefan Scheidegger folgendes:
> Thanks for your hints so far.
>
> I'm looking for both syntax simplicity and referential integrity. I'm
> using c++ with libpqxx, but I didn't find a good object-relational
> mapper. And I'm too lazy to implement a whole persistency layer as I
> don't have a huge DB with many relations.
>
> I tried Andreas' suggestion with a RULE for INSERT on a VIEW. I
> created the VIEW composing my table with customers and orders:
>
> CREATE VIEW vw_customer_insert AS SELECT * FROM tbl_customer,
> tbl_order WHERE cust_id = ord_customer;
>
> Then I added a rule for the inserting: CREATE RULE rl_customer_insert
> AS ON INSERT TO vw_customer_insert DO INSTEAD ( INSERT INTO
> tbl_customer VALUES (DEFAULT, new.cust_name, new.cust_address); INSERT
> INTO tbl_order VALUES (NEW.ord_pieces, NEW.ord_productname,
> NEW.ord_price, currval('"tbl_cusomer_cust_id_seq"')););
>
> But this results in the same problem: It works fine if I insert just
> one new customer with one new order. But if I want to insert several
> new entries:

Insert the new customer only into the table if this customer doesn't
exist there. If the customer exist in the table, obtain the id for this
customer.

simplified:

- detect, if the customer exists
yes: obtain the id as id
no: insert and use currval() as id
- insert the order with the id

I would write a function for this.

Andreas
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Andreas Kretschmer
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