Hi,
1. efashion is sample data of mysql or sap bobi sample data ?
Efashion universe is based on the efashion.mdb file.You can find the mdb file from the server .location is installation directory\Program Files (x86)\SAP BusinessObjects\SAP BusinessObjects Enterprise XI 4.0\Samples\webi .If you want to access efashion universe form local machine then you need to create system DSN on your local system and point to the local copy of efashion.mdb file.
2.how to create univers in udt ? all steps pls ?
Before create a universe you need to understand the concepts.
Here is the link of UDT user guide.
https://help.sap.com/businessobject/product_guides/boexir4/en/xi4_universe_design_tool_en.pdf
Similarly you can get the copy of IDT and how to create UNX universe from google.search on google you will get lots of documentation on concepts.
Information design tool 4.0: Concept - Create a universe
3 how to resolve loops and traps ? is there any logic to resolve loops n traps?
Similarly search on google you will get the documents on loops and traps concepts.
Some are
Dave’s Adventures in Business Intelligence » Designer SQL Traps
Dave’s Adventures in Business Intelligence » Context Versus Alias Overview
Amit