Two tables having many to many relationship can not be linked together directly. They need a third table which is a link table / bridge table to link the two tables.
Ex - Table Book , Table Authors
A Book can have more than one author and an author can write more than one book.
To link these two tables a third table Book_Author is needed which stores the primary keys of the two tables as Foreign keys.
Table Book_Author Columns Book_ID(FK), Author_ID(FK)
All the existing combinations of Books and Authors are stored in this third table.
Ex - Table Book , Table Authors
A Book can have more than one author and an author can write more than one book.
To link these two tables a third table Book_Author is needed which stores the primary keys of the two tables as Foreign keys.
Table Book_Author Columns Book_ID(FK), Author_ID(FK)
All the existing combinations of Books and Authors are stored in this third table.
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Hi mate,
ReplyDeleteThis is really nice information for all datastage scenarios. And you can read some more over here Datastage