How do I identify if DB is Down and QUIT TI Process

[Gollapudi]

Hi,

I have couple of TI process involved in updating a Dimension on daily basis..
one of them unwinds the hierarchies of dimension and then it fires another TI Process which fires an SQL Query to Oracle Database for the updated values.
Another will Construct the Hierarchies, it works fine if Database responds well.

But, in-case if DB is down...

1st TI Process will unwind the Hierarchies
2nd TI Process Will fail
3rd TI Process will construct Hierarchies and all goes under "Unknown"/"Orphans" level. :(

So now I am looking for some TI function or Technic where I can check the status of DB if its Up and running, if not wanted to Stop TI process (PROCESSQUIT) before its gonna unwind the dimension.

Appreciate your thoughts.