The situation is thus:

We are building an application (using a PHP frontend - 4.3.3 ) that processes large 
amounts of customer data (in some cases GB). During the processing we run queries 
where we compare the customer data to a number of rules tables (in a number of rules 
databases), e.g :

INSERT INTO customer_db.customer_table_2
SELECT a.field_one, b.field_two
FROM customer_db.customer_table_1 a, rules_db.rules_table_1 b
WHERE a.field_id = b.field_id

Originally, we kept all the DBs on a single database. However, of late, I decided to 
split the customer data as some customers have GB of data and take a lot longer than 
others. Therefore, I decided to split the customer databases to multiple boxes each 
running an installation of MySQL (4.0.15) with the rules databases on a seperate 
machine (also running MySQL 4.0.15). The idea being that I would only need to maintain 
a single copy of each of the rules db which would make updating  and maintenance 
easier. Unfortunately, this means that the above query then must look like this:

INSERT INTO customer_host.customer_db.customer_table_2
SELECT a.field_one, b.field_two
FROM customer_host.customer_db.customer_table_1 a, rules_host.rules_db.rules_table_1 b
WHERE a.field_id = b.field_id

Added to this I would have a seperate connection for each of the customer db and the 
rules db.

Currently, I have no idea how to achieve the above query given the new situation - 
mysql_query only accepts a single connection link. 

Does anyone know if there is anyway that I can perform the above query?

If I cannot - I have some alternatives but I hope someone will have a solution.


Rory McKinley
Nebula Solutions
+27 82 857 2391
"There are 10 kinds of people in this world, 
those who understand binary and those who don't" (Unknown)

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