Add support for Exasol 6

At the moment only Exasol4 is available as database. which presumably uses an old driver.

Can this be updated the latest Exasol version (6.2.5 as of now)?

I have tested the HOP Exasol$ connector against an Exasol 6.2.5 and it is buggy.

Example:
The SQL generated doublequotes the "schema.tablename" , which will cause a parsing error.

the correct syntax would be without doublequotes
SELECT * FROM schema.tablename;

Thanks!