Relating one table to several others

I'm building a database and want to have a couple tables (Notes,
Files) that relate to multiple other tables.  I would like to use a
UUID for this.

Is the Replication ID the right tool for this?  If not how do I create
an ID field that is unique across the database?

Here's what I am trying to do...

I have a table for Students.  I have a table for Classes.  I have a
table for Registrations.  I want to keep track of Notes for each
of those entities.  The Notes are the same for all three: Notes field,
Created
Timestamp, UserID.  Instead of adding three Notes tables (Class Notes,
Student Notes, Registration Notes), I want a single Notes table.  That
table will
have a field ParentID that relates it to Classes or Students or
Registrations.

How do I relate that Notes table to each of the three other parent
tables without a key conflict?

I need to define a key for each of the
three parents that will be unique across them.  Otherwise the Note for
Jane Smith (auto increment ID 17) will show up for Class Physics (also
auto increment ID 17).

Make sense?

I posted this on m.p.a. but they kept answering a question I didn't
ask and didn't need the answer to.

Thanks,
G

tblNotes
   notesId  autokey
   studentId (fk to tblStudent)
   classId (fk to tblClass)
   registrationId  (fk to tblRegistration)
   notes
   createdBy
   dateCreated
   etc

you'd have only one of studentId, classId, registrationId, implements
in the application

and it allows many notes, per ID

> otesId utokey
>> tudentId (fk to tblStudent)>
> lassId (fk to tblClass>
> egistrationId fk to tblRegistrati>n)
> >tes
> rea>edBy
> ateC>eated
>>>etc
>
> you'd have only one of studentId, classId, registrationId, imp>ements
> in the appl>ca>ion
>
> and it allows many notes, per ID

My normalization instincts tell me to avoid having two fields that
will always be null, but it may be good enough for government work.

No way to create a UUID?

tblNote
NoteID                AutoNumber
NoteType            Class, Student, Registration
NoteLinkID         Long, Allow duplicates
Message              Memo

Link your detail tables to NoteLinkID and use NoteType to select only notes
for Class, Student or Registration; of course you will not be able to
enforce referral integrity on NoteLinkID with this table layout.

Otherwise add a M-M table for each detail table

tblNote
NoteID                 AutoNumber
Message               Memo

tblClassNote
ClassID
NoteID

tblStudentNote
StudentID
NoteID

tblRegistrationNote
RegistrationID
NoteID

> NoteType lass, Student, Re>istration
> NoteLinkID Long, Al>ow duplicates
> Messa>e > emo
>
> Link your detail tables to NoteLinkID and use NoteType >o select only notes
> for Class, Student or Registration; of course you>will not be able to
> enforce referral integrity on NoteLinkID wit> t>is table layout.
>
> Otherwise add a M-M table f>r >ach detail>table
>
> tblNote
> NoteI> AutoN>mb>r
> Message > gt;Memo
>
> Cla>sID
> NoteI>
>
> tb>St>dentNote
> StudentID
>> NoteID
>
> tb>RegistrationNote
> Registrat>on>D
> NoteID- Hide quoted text -
>
> - Show quoted text -

referential integrity is the reason for my design
as to 'null' fields, many fields in many tables are null...