CREATE TABLE Group (
GroupID integer NOT NULL
, Name varchar(18)
, Description varchar(18)
, GroupType varchar(4) NOT NULL
-- all columns common to any group type
);
ALTER TABLE Group ADD CONSTRAINT pk_Group PRIMARY KEY (GroupID) ;
CREATE TABLE BusinessGroup (
GroupID integer NOT NULL
-- all columns specific to business groups
);
ALTER TABLE BusinessGroup
ADD CONSTRAINT pk_BusinessGroup PRIMARY KEY (GroupID)
, ADD CONSTRAINT fk1_BusinessGroup FOREIGN KEY (GroupID) REFERENCES Group(GroupID) ;
CREATE TABLE SocialGroup (
GroupID integer NOT NULL
-- all columns specific to social groups
);
ALTER TABLE SocialGroup
ADD CONSTRAINT pk_SocialGroup PRIMARY KEY (GroupID)
, ADD CONSTRAINT fk1_SocialGroup FOREIGN KEY (GroupID) REFERENCES Group(GroupID) ;
CREATE TABLE Person (
PersonID integer NOT NULL
, GroupID integer NOT NULL
);
ALTER TABLE Person
ADD CONSTRAINT pk_Person PRIMARY KEY (PersonID)
, ADD CONSTRAINT fk1_Person FOREIGN KEY (GroupID) REFERENCES Group(GroupID) ;