I am designing a database for law firm use. I have a "people" table and an "incident" table. It is a many to many relationship so I created a "junction" table that contains both the other primary keys (as foreign keys) and a primary key of its own. I now need to relate another table called "involved vehicles" to the junction table. This relationship is also a many to many. How does one create the relationship with a "junction" table? May a junction table have relationships other than with the 2 initial tables ("people" and "incident") that resulted in its creation? Thanks for your replies. Keep it simple for me, because I am!!!
I wouldn't add another key to your current 'junction' table that relates the people to the indcident.
The vehicle is related to the incident, so, create a foreign key from that table to a new table called 'vehicle' and allow a one-to-many join from there. That will allow you to get from the person to the vehicle by going through the incident table.