Thoughts on a Isolation/Security problem. - Mailing list pgsql-admin

Hi, i have run into the following problem.
Let me describe the context first.

When i joined the company(ies) i work for (a group of Shipping Mgmt/
Owenship/Agent companies), the only thing i was told when i started
designing the DB/Apps was just one company.

So i built everything into one single DB, and i wrote the apps
having one company in mind.

Our architecture is based on jboss3/postgresql (curenctly 7.4.12).
There is one .ear file, which authenticates users against a lotus
notes ldap server.

At the time, the corporate organisational model was a little bit wierd:
- Many Indepentent ownership companies
- Many Independent Mgmg companies
(but all busines was with one company in mind).

Each App user is a member of one or more ldap groups, each group
mapping to a mgmt company.

So i ended up with
- one DB with 173 tables
- one DB user (postgres)
- one .EAR application with 148,827 lines of code.

Now the requirements start to change.
The boss now bought some other types of vessels too.
So virtually there must be N separate distinct apps, where N is the number
of Mgmt companies (roughly one for every type of vessel), where each app
sees and manages only its data.

Moreover there are some apps that should see global data for some specific
tables. (like the crew data, people in the crew move from one type of
vessel to the other so they are not tied to a Mgmt company).

These new requirements are of legal nature, as well as of
operational. (People managing a type of vessels dont want to mess with
another type,
and auditors must see each company completely separated from the rest).

Doing it with extra code would be a real pain, since i would have to
refine
all security/authentication based on the groups (groups@mgmt_companies)
that a person belongs to. Also this way no inherent isolation/security
would hold.

Now i am thinking of restructuring the whole architecture as:
- Create one EAR app for every mgmt company
- Create one DB USER for every mgmg company
- Create one SCHEMA (same as the USER) for every mgmt company
(mgmtcompany1,mgmtcompany2,etc...)
- Find a way (links/xdoclet/eclipse?) to have *one* common code base for
the N EAR apps.
- Tweak with jboss*.xml to map java:comp/env/jdbc/<mgmt company>DB to
java:/<mgmt company>pgsql, where <mgmt company>pgsql authenticates
with the corresponding DB USER.
- Classify the tables into
  - The ones that apply to ALL mgmt companies (and leave them in the
public schema)
  - The ones that apply *only* to a mgmt company and so create one under
each SCHEMA
- Load the data in *each* SCHEMA, except the tables that apply to all.
- Define a process of "mgmt company"fying the tables in each schema (e.g.
delete from mgmtcompany1.vessels the vessels that dont belong to
mgmtcompany1, and so forth)
- Resolve FK constraint issues
- The default search_path in psql (whats the the equivalent in jdbc?) is
$user,public, so effectively *each* EAR will hit automagically the correct
mgmtcompanyN.* tables, or the public.* tables if these tables apply to all
mgmt companies.

With this way, the hard work is DB oriented, and not APP oriented.
However i wonder whether someone else has gone thru a similar process,
or if someone finds some assumption conceptually flawed.

Thanx for reading, and for any possible thoughts.

--
-Achilleus