>>>>
>>>>Creating PKs first for EACH table :-)
>>>
>>>Good suggestion. When I converted tables to SQL Server I added to each table an identity column. And I think of it as the surrogate PK field of the table. Each table also has a what I called in VFP a candidate field for which a user creates an entry (e.g. "CUSTOMER_ID"). When you are saying PK you mean the identity column or the candidate field (unique) that user enters?
>>
>>
>>Each table has to have Primary key.
>>The identity column is good for this (it is a little harder to manage it from the FrontEnd than uniqueidentifier (GIUD)).
>>But ALL referential integrity of the DB should be done via that Primary key.
>>All queries from your front end should have that PK in mind :o)
>>Usually (not necessary) PKs have nothing related to the information in the table. They just didn't hold any information about the record (like RECNO() in VFP).
>>That is because that way you easier could change the valuable information w/o need to change the related table.
>
>I am not sure that my referential integrity should be done via the Primary Key. Let me give you an example.
>Customer Table:
>PK CustPK (identity)
>CustomerID (unique entry, candidate key)
>
>Customer Order Table:
>CustomerID
>
>That is, the PK field of the parent table is not in the child (foreign) table. Only Candidate key is in the child (foreign) table. Therefore, my referential integrity will be set on the Candidate (unique) field, correct?


Yes,
Maybe I didn't express myself clear.
Yes the Referential integrity must be done via the PARENT table primary key and Foreign Key in the Child Table(s).
BUT every table (no matter parent or child it is) SHOULD have Primary key.

A very rough example why:

Parent Table 
--------------------------
Id           Name
--------------------------
1            Example 1
2            Example 2



Child Table 
--------------------------
ParentId     SomeOtherField
--------------------------
1            Example 1
1            Example 1
1            Example 1

2            Example 2

As you see you have 3 records in the child table for the ParentID = 1.
And HOW you will UPDATE/DELETE only the FIRST of these records if you didn't have PK for that TABLE?