Hi pdx971,
Customers and Leads are essentially the same thing, except that Leads do not sync with QuickBooks. Customers and Leads are both stored in the same table, the Customer table. There is a Yes/No field within the Customer table called IsLeadStatusOnly. This is the field that determines whether the record is a Customer or a Lead, and prevents or allows synchronization with QuickBooks. When Leads are converted to Customers, this flag is changed from True to False and the requisite information syncs over to QuickBooks.
Contacts are simply points of contact for your Customer or Lead. All Customers or Leads will have at least one Contact, but may have many more. All Contacts reside in the Contacts table.
Which table to put your field in really depends on whether it's the Customer or the Contact that should get a student number, or more specifically how you keep track of them. Does every Customer get one, and only one student number? If so, I'd say add the field to the Customer table. Do you have multiple Contacts that are students, but reside under the same Customer? Then you'd want to add the field to the Contacts table.
The Contacts table is already linked to the Customer table through the Customer dropdown. You could link the student number into the Contacts table through the Customer dropdown, but this would only be useful if you need to use the student number in screens or grids based off the Contacts table. It would also cause every Contact to have the same student number, since you're pulling it from the Customer, which would likely defeat the purpose of setting it up this way.
In terms of linking the Contacts table into the Customer table by adding a dropdown, I wouldn't do this. The relationship between the two tables is that Customers have many Contacts, but Contacts only have one Customer. Adding a Contact dropdown to the Customer table would circumvent this, which based on what you're trying to do wouldn't serve your purposes. I can see why you would want to add your student number field to either table, but you most likely won't need to link it into the other.
I think it would be a good opportunity for you to speak with a member of our Professional Services team, who can give you some more specific advice based on your unique workflow. Have you taken advantage of your free consulting hour?
- Justin