[RBG7-L] - Re: When is a one to many form appropriate wtih 3 tables

[David M. Blocker]

Michael   In 7.x, the term "Many to Many" on the form properties screen is not used in the classical relational database meaning. You have MULTIPLE one to many relationships and so in 7.x you should use the "Many to Many" setting (it really should read "Multiple One to Many" but who's quibbling!)   David Blocker [EMAIL PROTECTED] 781-784-1919 Fax: 781-784-1860 Cell: 339-206-0261 ----- Original Message ----- From: Michael Moser To: RBG7-L Mailing List Sent: Saturday, March 12, 2005 11:38 AM Subject: [RBG7-L] - When is a one to many form appropriate wtih 3 tables Hi All, I just joined the list server so this topic may have been addressed in the past.  If so I beg your indulgence one more time...   I am trying to understand when to use the one-to-many setting and when to use the many-to-many setting in the form properties when using R:Base 7.1 forms   With two tables, A and B, with a one-to-many (<) relationship between the two (A<B), the form properties are set to one-to-many and the form works correctly.   How ever if three tables are used (A, B, and C) such that: Table A has a Primary Key Table B has a Primary Key and a Foreign Key to A Table C has a Primary Key and a Foreign Key to B Table A and Table C have no common fields   Thus creating a one-to-many relationship between A and B, and a one-to-many relationship between B and C (A<B<C).  If a view AB was created from tables A and B, the view would also have a one-to-many relationship with table C (AB<C)   It seems that a form using A, B, and C would still be configured as one-to-many but in fact it must be set to many-to-many in order to work properly.  Setting the form to one-to-many with Tables A, B, and C causes the correct record set to be displayed for B, but all records are displayed for C.   So my question is this.  Can anyone provide an example of 3 tables that would use the one-to-many setting in a form?   Perhaps my understanding of one-to-many is inaccurate and all forms using 3 or more tables are many-to-many by definition, regardless of the relationships between the tables.   Thanks, Michael     Michael Moser EXAQ Micro Services www.exaq.com Phone: 916-966-8313 Fax: 916-966-8313