Three table link together using foreign key

Three table link together using foreign key

References

Reference NO 1

http://stackoverflow.com/questions/15193037/three-table-link-together-using-foreign-key

Reference NO 2

http://stackoverflow.com/questions/3763016/many-to-many-link-table-design-two-foreign-keys-only-or-an-additional-primary

Reference NO 3

http://dev.mysql.com/doc/refman/5.5/en/example-foreign-keys.html

Reference NO 4

http://www.w3resource.com/sql/joins/using-a-where-cluase-to-join-two-tables-related-by-a-single-column-primary-key-or-foriegn-key-pair.php

Reference NO 5

http://www.dbforums.com/ansi-sql/1215392-help-w-multiple-table-join-foreign-keys.html

Reference NO 6

http://www.teach-ict.com/as_a2_ict_new/ocr/AS_G061/315_database_concepts/terminology/miniweb/pg13.htm

Reference NO 7

http://docs.sqlalchemy.org/en/rel_0_7/orm/relationships.html

Reference NO 8

http://sqlmag.com/database-performance-tuning/sql-design-foreign-key