make sure update is finnished before making another select

I need to read a dbf record by record and make some updates in a database. The order of the records is very important! For every record I make an update in my database.
The problem is that I need to make sure the update is finnished before going to the next record, where I could need the previous records.
Mysql use threads that are not good in my situation, I need just one thread that takes the records one by one and makes the selects and updates on them being sure that the previous records are in the database.
How can I fo this? Any sugestion would be apreciated.