Is it unreasonable to assign a MySQL database to each user on my site?

Question

I\'m creating a user-based website. For each user, I\'ll need a few MySQL tables to store different types of information (that is, userInfo, quotesSubmitted, and ratesSubmit

Answer 1

Should I use one database, and many tables in that database, or many databases and few tables per database?

Neither, you should use one database, with a table for users, a table for quotes, a table for rates, etc.

You then have a column in (e.g.) your quotes table which says which user the quote is for.

CREATE TABLE user (
    user INT(10) UNSIGNED NOT NULL AUTO_INCREMENT PRIMARY KEY,
    ...
);

CREATE TABLE quote (
    quote INT(10) UNSIGNED NOT NULL AUTO_INCREMENT PRIMARY KEY,
    user INT(10) UNSIGNED NOT NULL,
    ...
);

CREATE TABLE rate (
    rate INT(10) UNSIGNED NOT NULL AUTO_INCREMENT PRIMARY KEY,
    user INT(10) UNSIGNED NOT NULL,
    ...
 );

You then use SQL JOINs in your SELECT statements to link the tables together.

EDIT - the above was assuming a many-to-one relationship between users and rates - where there are 'many-to-many' relationships you need a table for each sort of data, and then another table with rows for each User <-> Rate pair.