I keep running into problems like this and have another example of it that might be clearer.
I have 4 tables, Newsletters, Contacts, Industries, and Contact Groups. We send Newsletters to Contacts, either grouped by Industry or Contact Group. Contact Groups must be associated with an Industry. Contacts must be associated with an Industry, but not necessarily a Contact Group. For example, sometimes we would like to send a Newsletter to all Contacts who are in the real estate Industry, and sometimes, we only want to send newsletters to Contacts who are members of the Planet Earth Real Estate Board. So far, I have the following: Newsletters ------------------ id content contact_group_id (optional) industry_id (optional) Contacts ------------------ id name email industry_id (FK) contact_group_id (FK) (optional) Industries ------------------ id name Contact Groups ------------------ id name industry_id (FK) Are suggested solutions for this problem any different from those I've received for the previous example? The real problem is when a table (Newsletters) can be associated with 2 or more other tables (Contact Group or Industry). Thanks for any guidance. Marc -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/mysql?unsub=arch...@jab.org
