refer these links
http://www.researchgate.net/publication/2359510_Database_Design_for_Real-World_E-Commerce_Systems/file/d912f514403695774c.pdf
http://www.cis.drexel.edu/faculty/song/publications/p_IEEE-DE-Final.PDF
https://www.iusb.edu/math-compsci/_prior-thesis/SKhodali_thesis.pdf
http://www.z2media.com/sub-database/e-commerce.asp
http://comp.mq.edu.au/units/comp344/lectures/week03_Database_Schemas.pdf