Postgres: Remove PK constraints from edges
ALTER TABLE Message ADD PRIMARY KEY (id);
ALTER TABLE Forum ADD PRIMARY KEY (id);
ALTER TABLE Person ADD PRIMARY KEY (id);
-ALTER TABLE Forum_hasMember_Person ADD PRIMARY KEY (ForumId, PersonId);
-ALTER TABLE Forum_hasTag_Tag ADD PRIMARY KEY (ForumId, TagId);
-ALTER TABLE Person_hasInterest_Tag ADD PRIMARY KEY (PersonId, TagId);
-ALTER TABLE Person_knows_Person ADD PRIMARY KEY (Person1Id, Person2Id);
-ALTER TABLE Person_likes_Message ADD PRIMARY KEY (PersonId, id);
-ALTER TABLE Person_studyAt_University ADD PRIMARY KEY (PersonId, UniversityId);
-ALTER TABLE Person_workAt_Company ADD PRIMARY KEY (PersonId, CompanyId);
-ALTER TABLE Message_hasTag_Tag ADD PRIMARY KEY (id, TagId);
