I will not repeat the comments already made by the other Monks. I just wondered why you first select a list of addresses from the database and then plug in each address one by one in a new select statement to fetch the related IDs.

Unless you made some changes to the array of addresses, it should be possible to fetch the adresses and their IDs in one select statement. That will really speed-up your program.

When using databases, it is my experience that it is almost always "best" (= faster or less memory use or easier) to let the database do all the heavy lifting and only reserve the really difficult parts (like formatting or calculating or transforming the data) for your program.