Global-as-View
•Mediated schema:
•    Movie(title, dir, year, genre),
•    Schedule(cinema, title, time).
•Create View Movie AS
•   select *  from S1     [S1(title,dir,year,genre)]
•   union
•   select  * from S2     [S2(title, dir,year,genre)]
•   union                       [S3(title,dir), S4(title,year,genre)]
•   select S3.title, S3.dir, S4.year, S4.genre
•   from  S3, S4
•   where S3.title=S4.title
•
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