[ic] Interchange and SQL-Ledger / dblink / and psql triggers
andrewbaerg at yoursole.com
Tue Jan 25 16:09:37 EST 2005
On Tue, 25 Jan 2005 14:07:25 -0500, David Ratte wrote
> Hello all,
> Last week I posed a question regarding getting data into SQL-Ledger
> from a foreign application (i.e. interchange) and if anyone had any
> successes with this configuration.
> The use of dblink and triggers. This was very interesting because it
> means total independance of both applications as to keeping the data
> in sync -- and either application changing would not effect this
> stuff from working unless the db structure changed.
> Pardon my length, but some might find what I'm doing useful, and
> others to tell me why it won't work!
> Now this code here does work, but only if the sql-ledger customer
> table is in the same database as interchanges userdb.
> I guess the ultimate question is, Can dblink be used inside an
> plpgsql procedure, or is this just plain illegal??
As far as I know there is nothing illegal about this. Without taking the
time to troubleshoot your code, I will give you a snippet of some plpgsql
code using dblink which works for me. This code updates the userdb->company
field with the customer->name field on insert/update on the sql-ledger
customer table. The userdb and customer tables are in seperate databases,
but on the same host, but it should make no difference if the databases were
on different hosts. I am using postgresql 7.4.6
CREATE OR REPLACE FUNCTION customer_update()
RETURNS trigger AS
name := NEW.name;
customernumber := NEW.customernumber;
PERFORM dblink_connect(''dbname'',''dbname=dbname user=username'');
userdb_query := ''SELECT dblink_exec (''''dbname'''', ''''UPDATE userdb
SET company = ''''''
|| '''''' WHERE username = ''''''
|| '''''' '''')'';
LANGUAGE 'plpgsql' VOLATILE;
drop trigger customer_update on customer;
CREATE TRIGGER customer_update
FOR EACH ROW
EXECUTE PROCEDURE customer_update();
The quoting was enough to drive me crazy, but it does work very nicely. I am
currently customizing interchange+sql-ledger for a company and will be
making use of dblink for sql-ledger -> interchange synchronization.
> If I throw dblink into the mix, everything breaks:
> (working query)
> select * from dblink_exec('testdb','insert into customer (id,name)values
> (DEFAULT,''i24NULL'')'); dblink_exec
> INSERT 201975 1
> (1 row)
> this however, breaks down at hostname:
> ===BAD CODE SNIP===
> CREATE OR REPLACE FUNCTION user_update()
> RETURNS trigger AS
> select * from dblink('hostaddr=192.168.1.1 dbname=test
> user=test','select name from customer') as t1(name varchar) ;
> if exists( select 1 from dblink ('hostaddr=192.168.1.1 dbname=test
> user=test', 'select * from customer WHERE customer.name =
> (new.lname||'', ''||NEW.fname)') ) then
> ===END BAD CODE===
> Here's what I came up with (and it works, but so far without dblink):
> ===BEGIN CODE update_user.sql===
> CREATE OR REPLACE FUNCTION user_update()
> RETURNS trigger AS '
> --Let's see if the customer already exists in sql-ledger's customer
> --If the customer already exists, just update the existing record.
> if exists( select 1 from customer WHERE customer.name =
> (new.lname||'', ''||NEW.fname) ) then UPDATE customer SET --sql-
> ledger has only one name field, interchange has lastname and
> firstname -- Ucase(lcase(name)) normalizes 'jOe sMiTh' into 'Smith,
> Joe' to prevent dupes in sql-ledger name = (initcap(NEW.lname)
> ||'', '' || initcap(NEW.fname)), address1 = NEW.address1,
> address2=NEW.address2, city=NEW.city,
> state=NEW.state, zipcode=NEW.zip,
> email=NEW.email, phone=NEW.phone_day,
> contact=initcap(NEW.fname)||'' ''||initcap(NEW.lname) WHERE
> customer.name = (new.lname||'', ''||NEW.fname); else --Since we
> decided the customer did not exist, lets add a new customer record
> INSERT INTO customer ( name, address1, address2, city, state,
> zipcode, email, phone, contact ) VALUES (initcap(NEW.lname)||'', ''
> ||initcap(NEW.fname), NEW.address1, NEW.address2,
> NEW.city, NEW.state, NEW.zip,
> NEW.email, NEW.phone_day, initcap(NEW.fname)
> ||'' ''||initcap(NEW.lname));
> end if;
> RETURN NEW;
> LANGUAGE 'plpgsql' VOLATILE;
> --If the trigger already exists, get rid of it so we can re-create it
> DROP TRIGGER trans_update on transactions;
> CREATE TRIGGER trans_update
> BEFORE UPDATE
> ON transactions
> FOR EACH ROW
> ====END CODE====
> Thank you for your response, and please trim responses accordingly
> to keep mail size down.
> -Dave Ratte
> interchange-users mailing list
> interchange-users at icdevgroup.org
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