# Relationships - how to prevent key attributes from propagating in child

**URL:** <https://forums.toadworld.com/t/relationships-how-to-prevent-key-attributes-from-propagating-in-child/1948>\
**Category:** Toad Data Modeler\
**Created:** [April 2, 2009, 8:40pm UTC](https://forums.toadworld.com/t/relationships-how-to-prevent-key-attributes-from-propagating-in-child/1948 "2009-04-02T20:40:30Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![truenorth](https://avatars.discourse-cdn.com/v4/letter/t/3bc359/32.png) [@truenorth](https://forums.toadworld.com/u/truenorth)\
**Post date:** [April 2, 2009, 8:40pm UTC](https://forums.toadworld.com/t/relationships-how-to-prevent-key-attributes-from-propagating-in-child/1948/1 "2009-04-02T20:40:30Z")

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When I create a relationship between two tables, all key fields in the parent get propagated in the child, even though the child already has such fields, duplicating them. Worse yet, parent fields get listed in the child, even though those fields don’t exist in the child!

How do I correct this behavior?

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**Author:** ![vladka](https://sea1.discourse-cdn.com/quest/user_avatar/forums.toadworld.com/vladka/32/41_2.png) [@vladka](https://forums.toadworld.com/u/vladka)\
**Post date:** [April 3, 2009, 2:57am UTC](https://forums.toadworld.com/t/relationships-how-to-prevent-key-attributes-from-propagating-in-child/1948/2 "2009-04-03T02:57:16Z")

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Hello,

This is a correct behavior. In TDM, key attributes migrate from parent table to child table automatically when you create a relationship between them.

You don’t have to create the attributes in child tables manually. TDM will do it for you - as soon as you add the relationship.

When keys are duplicate, you can use the FK Mapping feature.

Please see the Help file | Index tab and type ‘fk’. Please see the following topics: foreign keys and fk mapping.

Also, I recommend you to watch the following flash movies:  
Create ERD - [http://modeling.inside.quest.com/entry.jspa?externalID=1667&categoryID=158](http://modeling.inside.quest.com/entry.jspa?externalID=1667&categoryID=158)  
FK mapping - [http://modeling.inside.quest.com/entry.jspa?externalID=1668&categoryID=158](http://modeling.inside.quest.com/entry.jspa?externalID=1668&categoryID=158)

and others at:  
[http://modeling.inside.quest.com/kbcategory.jspa?categoryID=158](http://modeling.inside.quest.com/kbcategory.jspa?categoryID=158)  
Please sort the movies by Title - Ascending order and start with the ‘Getting Started’ movies.

If you have any questions, please write me back. Thanks.

Regards,

Vladka