Access Parent Child relationship

Murray Brown
Murray Brown used Ask the Experts™
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In Microsoft Access table relationships, is every relationship a parent child relationship and what determines whether one is the parent and the other the child.

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Top Expert 2006
Commented:
Relationships between table are not mandatory. You only need to add them if u link a table
take for example, two tables
tblInvoice and tblInvoiceLine

in tblInvoice, u would hold details about the order
eg
ID (autonumber)
Name
Date etc

Now if 5 items were ordered, rather than duplicating the above, you would create another table. This could be considered your child table
it has details of the items plus a secondary (foreign) key. This field holds the autonumber of tblInvoice

this is called a one to many

Is this what u were referring to when u said parent/child?
My observations are that a link from a PK to a non-pk field produces a parent-child (one-many) link. (PK table is the parent)
A link from a PK to  PK produces a one-one link.
A link from a non-PK to a non-PK field produces a link described as Indeterminate.
Top Expert 2016

Commented:
one to many relationship

one is the parent and the many are the child

see this link for more info
http://support.microsoft.com/?kbid=304467
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DatabaseMX (Joe Anderson - Microsoft Access MVP)Database Architect / Application Developer
Top Expert 2007
Commented:
DatabaseMX (Joe Anderson - Microsoft Access MVP)Database Architect / Application Developer
Top Expert 2007

Commented:
Some relationships a Many to Many, usually requiring a third 'join' (or 'union') table.  And examples is:

One Teacher, Many Classes  <>  One Class , Many Teachers ..... with a table to link the common  ID's

Also,

One Teacher, Many Students<>  One Student, Many Teachers ..... with a table to link the common  ID's

mx
Murray BrownASP.net/VSTO Developer

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Commented:
Thanks very much for the rapid answers

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