Zeoslib Portal

Hi,
I want execute queries without use zdbo components.
So, i found in Knowledge base this sample :

...
Statement := MyZConnection.DbcConnection.CreateStatement;
ResultSet := Statement.ExecuteQuery('SELECT * FROM MyTable');
Metadata := ResultSet.GetMetadata;
...

My question is:
Must I destroy object referenced by interfaces Statement, ResultSet and Metadata ? And if yes, how ?

Thanks a lot.
David

PS: Excuse my bad English, I am French.