It is possible to do what you want with Perl, but it will not be easy (believe me I had to do it myself and it took me a lot of time and sweat and cursing and ...), so perhaps one should consider a different approach.

I read "I have a flat file exported from a database" and I wonder whether you can directly access this database.

As you know Perl has the wonderful DBI /DBD family of modules which allow you to work with most types of databases (including MS Access).

So if you need to transfer data from one database to another, DBI/DBD is the obvious way to go: write some SQL to select the data you need, execute this SQL, save the results in an array or hash-variable, then insert the data in the other database.

If you cannot speak to the original database, perhaps you can change the export format. A real "CSV" format seems not possible (due to the repeating fields at the end), but an 'XML' format is ideal. XML is very well suited for data-interchange.

One last comment: Access is perhaps not the best choice when you have a lot of data to transfer. After a few thousand records the performance really goes down (if not worse and it crashes on you). Before that happens you should investigate into using a real database server (MySQL, Postgres, to name but a few).