setp 1. First create New Edit.

setp 2.Create New Table

First Table Name is NParentRel

then drag and drop the newly created Edt in NParentRel Table

setp 3.Create Index for new created EDT in NParentRel Table

the properties on index is AllowDuplicates to No

and Alternativekey to Yes

setp 4.then select the NParentRel Table and right click on it select properties sheet set the "primary index" property i.e the newly created index

setp 5.Then go to Edt and right click on it ,select property sheet then go to "Reference Table" property Set it to NParentRel Table Name

setp 6.Create a Second Table i.e child Table

setp 7.Then Drag and drop the EDT

then it will prompt the one dialog box

in that dialog box click Yes button then lookup will created on that field.