Extracting a data

I have to extract some data from a table in Database A to Database B.
The table structure on both the d/b are same. A daily job will extract the data from A to B using a DB link.

What is the best way to ensure that only newly inserted records in the table in A is extracted to the table in B.
Can somebody give me the common logic used.

Do you have a timestamp or sequence column in the table, if so this is probaly the best way to select the data to be copied. Otherwise you could consider using MERGE

HTH

Thanx jovery,
Can u pls explain me how this MERGE can be done....?