ERD Visio 2010 Drawing - Table Relationships

Amour22015
Amour22015 used Ask the Experts™
on
Hi  Experts,

I have several Tables that I have drawn and am currently drawing the relationships between table(s).

I have noticed that some of the connectors have Parent/Child relationships like:
Parent: TblParent and Child: TblChild

And other(s) have:

Parent: TblParent and Child: "Nothing"

Or:

Parent: "Nothing" and Child: "Nothing"

Or:
Parent "Nothing" and Child: TblChild

What determines this?
I am missing something?
I am not doing something correct?

I want them all to be:
Parent: TblParent and Child: TblChild


Please help and Thanks....
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Distinguished Expert 2017

Commented:
What is the relationship type? Direction, one to one, one to many, many to many?

Do you have the database design ?
You can have a reference relationship .........

Without the specifics, it is merely a guess on my part.

Author

Commented:
Hi,

Thanks for helping me.

All I am looking for is why the:
Parent: tblparent
Child: tblchild

is indicated on some of the relationships, yet not on others?

and how to fix this.


There must be a way to turn both on.

Please help and thanks
Distinguished Expert 2017
Commented:
You have to look at what the columns are that the relationships represent.
i.e. a primary key in one table will be reflected as a parent to an entry in the second table(child).
If the reference in table A and table B are merely referential, there is no parent/child relationship.

user to sale invoices would be a parent to child i.e. a user can have multiple sales invoices
a sale invoice to a list of items, one sale invoice can have multiple items. this is a reference table and there is no parent/child relationship, or at least I think so.

There could be many users with different sales invoices where each sales invoice can reference an item.

Lets try it this, way. A parent takes their child and a group of the child's friends. There is one parent/child relationship and adult to children reference. When parents drop their children to a third party, there is no parent-child relationship. there is only adult/supervisory to young people .......

What is it you want fixed.

What do you want the ERD to reflect on these relationships, parent/child?
Note parent/child means the Parent has to be a unique record.

Author

Commented:
Thank you this is what I am looking for...

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