Forum Discussion
Helper IMCQ on PL 300
I was solving PL300 mcq :-
My answer for Product and Productsubcategory is Left Outer Join and Productsubcategory and productcategory is Inner Join.
The MCQ answer were Product and Productsubcategory is Inner Join and Productsubcategory and productcategory is Left Outer Join.
I am not sure if the mcq answer is correct. Please need suggestion and help with detailed explanation.
Every product has a guaranteed subcategory. So inner join is the fastest.
Not every subcategory has a category (what a mess!). So left join is your only option.
2 Replies
- lbendlin
Super User
Every product has a guaranteed subcategory. So inner join is the fastest.
Not every subcategory has a category (what a mess!). So left join is your only option.
Hi subha257 ，
Every Product has a ProductSubCategory. Not every ProductSubCategory has a parent ProductCategory.
We can infer the following relationships:
There is a mandatory relationship from Product to ProductSubCategory (every product must have a subcategory).
There is an optional relationship from ProductSubCategory to ProductCategory (a subcategory might or might not have a category).Since every product needs to have a subcategory, this would be an Inner Join, because we want only the products that have valid subcategories.
And then left join previous result and ProductCategory:
Best Regards,
Gao
Community Support TeamIf there is any post helps, then please consider Accept it as the solution to help the other members find it more quickly.
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