I would like to develop an application that could work with different types of database (Oracle, Informix, db2, Access, MySQL ...).

Can anybody confirm me if do understand how JDBC works.
Here is what I understand of JDBC :

In the Java code of the application, we include SQL Queries that are specific to JAVA (kind of "Java SQL").
Then, it is possible to connect the application to every kind of database and the driver JDBC (for Oracle, Informix, db2, Access, MySQL ...) will "translate" the queries so that the RDBMS can understand the queries.

Am I right?

Besides, I heard that while the access to the data with JDBC is slower than with ODBC. Do you have information about that ?

Thank you very much if you have any information that could help me.