meaning of the use case effort attribute

[fausto bertoli]

If I define a SQL query to extract alluse case attributes for the databse referring the t_object table, I see that one of the available attributes is name effort.
What does i tmeans?
Is it linked with the effort window into the project management section?
I tried to assing there an effort element to a give use case but the use case effort attributes is always 0 in the search window.
Suggestions?

[qwerty]

It's heritage.

q.