difference between alias and duplicate tables in OBIEE

Tell me about these alias and duplicate tables in repository of obiee and how they differ from one another and when we work on these tables

I don't think this is an appropriate forum for OBIEE. Oracle has a forum for that which is located on http://forums.oracle.com/forums/forum.jspa?forumID=378. Unless you want to discuss a particular dimensional modelling issue (duplicate?), in which case you will need to elaborate what the issue is so we can understand and response to it.

http://gerardnico.com/wiki/dat/bobj/bobj_join
check with link
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