Help needed with db structure
You don't need a table per stock symbol, you just need one of the fields in the table to be the stock symbol. The table might be called StockPrices and its fields might be

ticker_symbol - the stock ticker symbol
time - the time of the stock quote
price - the price of the stock at that time

As long as ticker_symbol is an indexed field you can do powerful queries like SELECT time,price FROM StockPrices WHERE ticker_symbol='GOOG' ORDER BY time DESC and they will be very efficient. You can also store as many symbols as you like in this table.
You could add other tables for dividends, volume information and such. In all cases you probably have a composite key of ticker_symbol and time.
I'm developing a web app that uses stock data. The stock data can be stored in:

Files 
DB

The structure of the data is simple: there's a daily set and a weekly set. If files are used, then I can store a file per symbol/set, such as GOOGLE_DAILY and GOOGLE_WEEKLY. Each set includes a simple list of (Date, open/hight/low/close, volume, dividend) fields.
But how can I do it with DB? Should I use relational or other db? I thought about using 2 tables per each symbol, but that would generate thousands of tables, which doesn't feel right.
Thanks.