File export/import

[gus]

Hi folks,

I am totally new to Typo3 and I have the following business problem: I
have a custom extention into typo3 cms corresponding to a database
table for storing of books, and each record (book) of the table can
have one electronic document attached (the pdf version of the book);
how can I extract this pdf using a massive bulk export procedure? On
the other side, I need to massively insert records from a SQL server
table to this Typo3 database table and this import procedure should
also import the pdf (associated to the SQL Server table rows) into the
Typo3 CMS; do you have any idea on the approach to follow? How does
Typo3 internally manage attached files? I noticed that in the book
table there is an exadecimal field called "file_name" or something
like that.

many thanks