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.