I have 3000 symbols and each symbol will have a blob data everyday.
In one year, there will be 3000*365 blob records.
And I will insert these records per yearly database. ex)db_2011.fdb

I am thinking of creating a table having (symbol_date, blob) structure.
So, the records will look like
(s0001_20110101, b0001_20110101)
...
(s0001_20111231, b0001_20111231)
....
....
(s3000_20110101, b0001_20110101)
...
(s3000_20111231, b0001_20111231)

And my main most frequent query will be to find a record corresponding to a symbol and a specific date. ex) (s_1004, b1004_20110728)

Also main everyday insert will be to insert today's new record for each symbol. That is 3000 inserts once everyday.
And everyday I will have to find the record having the most recent date.

Two possible structures.

[1] (Symbol, Date, Blob) => Symbol primary and Date is secondary key
[2] (Symbol_Date, Blob) => Symbol_Date is single primary key

At the moment I was experimenting with [2] simply because of easiness.

What structure would fit better in terms of performance and ease of use? And why?

thx