SQL CLI and connecting to RDBs

I ran across this today...

" What is CLI Server Mode?

Server mode was introduced in V4R2 in a functional PTF. The reason for running 
in SQL server mode is that many applications have the need to act as database 
servers. This means that a single job will execute SQL requests on behalf of 
multiple users. In our current SQL implementation, this does not work for 3 
reasons:

1) A single job can only have one commit transaction per activation group

2) A single job can only connect to an RDB once

3) All SQL statements run under the job's user profile, regardless of the 
userid passed in on the connect

SQL server mode will solve these 3 problems by routing all SQL statements to a 
separate job. ..."

The document is:

http://www-03.ibm.com/servers/eserver/iseries/db2/clifaq.htm#header_3

The pieces that interest me are:

  2) A single job can only connect to an RDB once

...along with:

  "SQL server mode will solve these 3 problems..."

Does anybody have a useful explanation of what those two items mean together?

Tom Liotta