assigning ID's

Do you have some rule of thumb when assigning ID's for the following tables in the database:
1. Products
2. orders
3. users

the shop intending to use the database can be considered medium with products upto 2000, customers upto 200000.
I am hopping the ID are future proof.

Normally a primary key ID column is set to be an integer. the rule of thumb is to set it to Auto Increment, this will start at 1 and automatically increment to the next value each time a new record is added. the value of an integer can be up to 2,147,483,647.

That I know of course. may be my question was not clear.
I am assuming the max. number of items in the shop are 2000 items:
PRODUCTS ID from 1-2000

I do not know how many customers AND orders there will be. But I can imagine 200,000 customers and 2,000,000 orders:
CUSTOMERS ID from 2000-200000
ORDERS ID from 200,001-2,000,000

I am assigning the other tables ID's in that way. Is this the right way to do?
Or I can have the same set of integers for any ID without any problem such as this one
CUSTOMERS ID from 2000-200000
ORDERS ID from 2000-200000

If the database is designed right way from the beginning, it would make less headache in the future incase I need to improve it.

the id column in each table can contain the same values.

CUSTOMERS ID from 2000-200000
ORDERS ID from 2000-200000


is perfectly acceptable.

Hey Jason,

I think you meant to say acceptable.

that's what I get for relying on spell check....


thanks.