Question

I have a database schema that includes the following tables:

• People
• Organisations
• RelationshipTypes

What I want to design is a concept of a relationship type, and then the structure of that relationship. So a person could have a type of relationship with another person or with an organisation. An organisation can have a relationship with another organisation or a person.

I’ve got the following schema, but I’d like to run it past the community to see if there are any better ideas.

CREATE TABLE OrganisationRelationshipTypes
(
    ID INT PRIMARY KEY IDENTITY,
    RelationshipTypeID INT NOT NULL REFERENCES RelationshipTypes(ID)
    FromOrganisationID INT NOT NULL REFERENCES Organisations(ID),
    ToOrganisationID INT NOT NULL REFERENCES Organisations(ID)
)

CREATE TABLE PersonRelationshipTypes
(
    ID INT PRIMARY KEY IDENTITY,
    RelationshipTypeID INT NOT NULL REFERENCES RelationshipTypes(ID),
    FromPersonID INT NOT NULL REFERENCES People(ID),
    ToPersonID INT NOT NULL REFERENCES People(ID)
)

CREATE TABLE OrganisationPersonRelationshipTypes
(
    ID INT PRIMARY KEY IDENTITY,
    RelationshipTypeID INT NOT NULL REFERENCES RelationshipTypes(ID)
    FromOrganisationID INT NOT NULL REFERENCES Organisations(ID),
    ToPersonID INT NOT NULL REFERENCES People(ID)
)

CREATE TABLE PersonOrganisationRelationshipTypes
(
    ID INT PRIMARY KEY IDENTITY,
    RelationshipTypeID INT NOT NULL REFERENCES RelationshipTypes(ID)
    FromPersonID INT NOT NULL REFERENCES People(ID),
    ToOrganisationID INT NOT NULL REFERENCES Organisations(ID)
)

The idea of this is that it covers such scenarios:

• An organisation has done business with another organisation
• A person is another person’s father
• An organisation recently hired the person
• A person recently worked for the organisation

This schema seems a little messy, but at the minute I can’t think of an alternative.

Do you have any suggestions?

Answer 1

Party is often used as a generic term for person or organization, as in “parties in contract” …