How to implement multi-companies schemas?

Question

I need to implement a multi-companies data base. There will be only one server and all the clients of the differents companies will have access to this server.
How can I do this?
- Tables with a company column
- A schema per company
Any suggestion?
Regards

Answer 1

In my mind, the simplest possible thing that could work would be a single schema where most if not all tables had a COMPANY_ID column, a context that gets populated with the COMPANY_ID, and a view layer that reads the data from the context to limit the set of rows that the current session can access. That way there is only one view that provides company-specific data regardless of the company rather than one view per company. This would be relatively similar to the VPD solution replacing policies on tables with views.
You can create a context
CREATE OR REPLACE CONTEXT your_context_name USING your_authorization_pkg;where YOUR_AUTHORIZATION_PKG is a package that determines which COMPANY_ID a particular session will have access to. That's one of the more vulnerable pieces of the infrastructure here, so you'll want to make sure that it is well secured. Within YOUR_AUTHORIZATION_PKG, you would set the value of the context
DBMS_SESSION.SET_CONTEXT( 'YOUR_CONTEXT_NAME', 'COMPANY_ID', <<computed company id>> )where <<computed company id>> is the company ID that your package has determined the user has access to. Your view layer can then reference the value in the context
CREATE OR REPLACE VIEW vw_employee
AS
SELECT *
  FROM employee
WHERE company_id = SYS_CONTEXT( 'YOUR_CONTEXT_NAME', 'COMPANY_ID' );This isn't as easy or as secure as VPD, but it's often close enough.
Justin