Re: business users services

[Rick James]

> So,changing the data type for b_users means changing it also for the user_id...given the fact that the users table contains all the users of the site(business users and regular users),which means a bigger INT is required,do you still think is a good idea to use MEDIUMINT or SMALLINT?

True. You would need to change it consistently across all tables where it is used. And it would need to be big enough for all reasonable growth.

If there is a chance that 16 million won't be enough, then leave it as INT.
If 64K is risky, 16M might be a safe limit.
It all depends on your application. I have some ids that are safely declared TINYINT UNSIGNED (0..255).
I almost never see a real need for BIGINT -- which is needed if you expect to go beyond 4 billion (the limit if INT UNSIGNED).
(Note that your INTs are SIGNED, with a range of -2 billion to +2 billion. UNSIGNED is better for ids, but that is not a big deal here.)

Another cautionary note:
> `price` decimal(6,2) DEFAULT NULL
Will the price never go over 9999.99?
Will you never have to use non-Euro / non-dollar currency? Some currencies need more decimal places than 2.