Just to reiterate something about the built in Oracle accounts:
SYSTEM is a sample DBA account with some of the more common DBA rights already
granted to it – but not all of them. In fact, it’s missing a bunch.
But it’s meant to demonstrate the kind of accounts one should create. The
recommendation is that people create a DBA role or template of rights and then
grant that to the DBA schemas or users they create. That SYSTEM is just an
example to let you hit the ground running in a proper fashion – but not
with all a good DBA will need.
SYS is the magic account much like root on unix/linux and administrator on
windows. You should only connect to the database as SYS rarely – for tasks
that strictly require SYS access in order to function. Examples include Oracle
patches, upgrades, certain startup/shutdown/back/recovery options and some
scripts run to add additional functions the database – e.g. stats pack
table and package creation.
As such, I would not expect people to have a toad connection defined for SYS
– since they should only be using this rarely and for very isolated tasks
– and not for general use.