Application Data Storage Question

I'm working on an application that will need to store
all sent and received emails in logical groupings - in
my case, each transaction will have an email history
associated with it.

i can conceive of two ways to store the email data.

1. stick all pertinent email info in a db linked to
the transaction id.
2. create a transaction id directory in the file
system and store a file for each email sent/received
with all the pertinent info within that file.

the user needs this functionality to provide an
archive of the transaction.

i'm not experienced enough to know the pros and cons
of either process, or if there is a better process i
haven't thought of.

tia...

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