Updation in tables involving multiple conditions (one to many relationship) - sql

Question

I have created three tables like Product, Brands and ProductBrands in ms sql server
These tables contains data as the following
Products (PId - PName - PDescription)
1 - Mobiles - blah blah
2 - T.V - blah blah
3 - A.C - blah blah
Brands (BId - BName)
1 - Samsung
2 - Sony
3 - L.G
4 - Apple
ProductsBrands (PBId - PId - BId)
1 - 1 - 1
2 - 1 - 2
3 - 1 - 3
4 - 2 - 1
5 - 2 - 3
...
...
Now I have to perform update operation on Product tables on the following conditions
If user will select product "let's say Mobile", and he will select Samsung and L.G only
so for this requirement, the updation in ProductsBrands should be like this
ProductsBrands (PBId - PId - BId)
1 - 1 - 1
{2 - 1 - 2} should be deleted
3 - 1 - 3
...
...
If user will select product "let's say Mobile", and he will select Apple
so for this requirement, the updation in ProductsBrands should be like this
ProductsBrands (PBId - PId - BId)
1 - 1 - 1
2 - 1 - 2
3 - 1 - 3
4 - 2 - 1
5 - 2 - 3
6 - 1 - 4 {new entry is made}
If user will select product "let's say Mobile", and he will select Samsung, L.G and Apple
so for this requirement, the updation in ProductsBrands should be like this
ProductsBrands (PBId - PId - BId)
1 - 1 - 1
{2 - 1 - 2} should be deleted
3 - 1 - 3
4 - 2 - 1
5 - 2 - 3
6 - 1 - 4 {new entry is made}
Now I am very very confused how to write stored procedure for all above conditions
Please help me!!!

Answer 1

Your scenario was a little ambiguous for me. So lets simplify it as follow, and check if I got it correct or not:
You want to Insert or Delete or even Update a record or a set of records in a table(let say tbl1), whenever a condition(let say con1) is correct(let say if con1 is correct then Insert should me made, otherwise Delete or Update should be made).
If this is what you are looking for, then you could make a use of MERGE statement(Read More).
If this is what you are looking for, and you have problem with MERGE statement, please tell us to clarify it.
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