It's mentioned In particular, a many-to-many association may always be represented as two many-to-one associations to an intervening class.
BUT the actual code (with not much explaination) is given as :
Now here there is only one <many-to-one> mapping instead of 2 ? Moreover in the downloadable code, there are 4 ways given which are missing in the book...
WAY 1: This uses collections on both sides and uses <many-to-many> element. There are no additional columns in the underlying many-to-many join table.. [ I understood this scenario completely]
WAY 2: [ I didn't understood this case completely ] They are using 2 one-to-many associations. They introduced an intermediate class called CategorizedItem. From the code it seems that they have 1 * * 1 Category -------> CategorizedItem -------->Item
Q-1 How these 1->*, *-> 1 associations is equivalent to * -> * association ?
Q-2 In the book, they have define CategorizedItem as component with parent as category. If CategorizedItem is component, then why <component> ismissing and moreover why CategorizedItem properties don't go in Category table?