Dead Lock Explained

Boss said to secretary: For a week we will go abroad, so make arrangement.
Secretary makes call to Husband: For a week my boss and I will be going abroad, you look after yourself.
Husband makes call to secret lover: My wife is going abroad for a week, so lets spend the week together.
Secret lover makes call to small boy whom she is giving private tution: I have work for a week, so you need not come for class.
Small boy makes call to his grandfather: Grandpa, for a week I don't have class 'coz my teacher is busy. Lets spend the week together.
Grandpa (the 1st boss in the beginning of this story) makes call to his secretary: This week I am spending my time with my grandson. We cannot attend that meeting.
Secretary makes call to her husband: This week my boss has some work, we cancelled our trip.
Husband makes call to secret lover: We cannot spend this week together, my wife has cancelled her trip.
Secret lover makes call to small boy whom she is giving private tution: This week we will have class as usual.
Small boy makes call to his grandfather: Grandpa, my teacher said this week I have to attend class. Sorry I can't give you company.
Grandpa (the boss) makes call to his secretary: Don't worry this week we will attend that meeting, so make arrangement.......

The situation like this in terms of Oracle will result

ORA-00060: deadlock detected while waiting for resource

So
Deadlock occurs when a session wants a resource held by another
session, but that session also wants a resource held by the first
session.