# Returning one component of a mangled foreign key

Availability-note[Deprecated](https://help.talend.com/r/en-US/Cloud/labels-on-talend-help-center/availability-deprecated)

This content is deprecated.

Available in...

* Data Fabric
* MDM Platform
* Qlik Cloud Enterprise Edition
* Qlik Talend Cloud Enterprise Edition
* Qlik Talend Cloud Premium Edition

The getFK routine allows you to return one component of a mangled foreign key using tMap, for example:

![Map editor.](https://help.qlik.com/talend/en-US/studio-user-guide/Resources/images/getFK_Routines.png)

You must use the getFK MDM routine in the lookup table in the Map Editor. Using the getFK routine in the editor, you can add/remove/update the foreign key components. In the above capture, the routine helps you to return the name component in the mangled foreign key.

You must do the same in a reversed case and use the createFK routine to return the foreign key string by a single key.