>Dear Mark,
>1. My application design for accessing their own data.
>2. I have no idea for security for each own company.do you know oracle or MS SQL have some tenique for setup security for this case.
>
>Regards,
>
>Sanit kiriwong.

If you keep all company data under the same schema [user ID], then any one with SELECT privilges on those tables can retrieve data for any company. If you create a schema for each company, then you can prevent users from one company accessing data from another company.