I mean you need to set up separate databases.
It should not be like table 1 ..9 for one database and table 10..18 for another client.
It can also be achieved by storing all the client data into a single set of tables by maintaining some sort of flag, but that will involve high risk factor for data security.
Just imagine what happens when report of one client containing all the sensitive data goes to another client (may be a potential competitor) by mistake.