问题
I have a UML diagram of what I need my database schema to look like. This diagram includes roles and cardinality. How can I enforce cardinality in Postgres?
回答1:
Cardinality is enforced by using constraints.
http://www.postgresql.org/docs/8.1/static/ddl-constraints.html
来源：https://stackoverflow.com/questions/3135206/cardinality-in-postgresql