subentities

[burdenslifted]

What's the best way to deal with data that is really only relevant to specific subgroups of an entity?

I'm working on a directory of ORGANIZATIONS and PEOPLE. Organizations all have contact info (address, phone, website) and orgtype (e.g., church, school, charity). But some information is only relevant to certain kinds of organizations (e.g., service times for churches, grade levels for schools).

I can see three options (TABLES in caps, fields in lowercase).

Option 1:

ORGANIZATIONS

_kp_organization

address

phone

website

orgtype

grades (blank for non-schools)

service times (blank for non-churches)

Option 2:

CHURCHES

_kp_church

address

phone

website

service times

SCHOOLS

_kp_school

address

phone

website

grades

CHARITIES

_kp_charity

address

phone

website

OTHER ORGANIZATIONS

_kp_org

address

phone

website

Option 3:

ORGANIZATIONS

_kp_organization

address

phone

website

orgtype

CHURCHES

_kf_organization

service times

SCHOOLS

_kf_organization

grades

Organizations are related to one another organizations (e.g., churches can have schools or charities) as well as to people. Can such relationships be managed better with one of these structures than another? Is there a better structure that I'm not considering?