you need to connect only one time and disconnect also.

i connect in my starting program to the database, works with this all tables from this db in all programs and subprograms called from the start application.

I you are interessed, i can send you demo sql programs how to do this! (please email or pm)

First, simple answers to your questions:
1 -> no
2 -> no
3 -> I cannot see any use for this.

Have a look at your Net Express documentation (Help), chapter "Database Access Guide":
-> Part 1 Database Access Facilities -> Multiple Program Modules
-> Part 2 OpenESQL -> Database Connections

The problem is that the database connect time is very small. So if I connect at the first pllication and the user is in longer, the connection will be drop from MYSQL-Server and I can not find out if this happens. Therefore.

The MYSQL-Timeout is on 15 minutes. So. If the user is doing nothing in between 15 minutes: ByeBye Connection.

I ask the DB-Admin to make this time longer, but they will not do because of security-level.

And now?