How could i get the task's startdate?

[violet]

We want to get the task's startdate and task's enddate for calculate the task's cost time.

But we can not get the task.starttime.Also we can not
get the time when a user take an ownership of the task.

We used the hsqldb DatabaseManager to connect to the alfresco DB.
And we found the task.starttime in DB ,all the values are "null".

Any help will be really appreciated!

[violet]

I'm sorry for that i'v made a mistake….

It seems that i should not post the question here…

And  i have posted the  question in the forum "Workflow Administration"..

Anyone who has interest about it may track the below link:
http://forums.alfresco.com/viewtopic.php?f=34&t=11446