Hallo everyone,

I am using an universal database client. This client provides all drivers for most popular DBMS for the connectivity. The drivers are JDBC because the client is written in Java.

I successfully connect to my db2 Server. I have also Oracle and MySQL Servers.

I would like to build a datawarehouse from these heterogenous DBMS. But without using any ETL-Tool. I would like to use only SQL.

Conceptual question:
The SQL Client provides also JDBC for Oracle and MySQL. But each of the connection is built separately, so that I can not combine the objects across.

What is the best practise for this case?

Table 1 is from Oracle
Table 2 is from db2
Table 3 is from MySQL
I get table 4 from joining table 1, 2, and 3. How can I do this?

Thank you for the comments.