--> t3 : t3_id (pk), t3_info, t3_t1_id (foreign key)
Suppose that we have 1 millions of records in t1,
5 millions of records in t2,
4 millions of records in t3
the goal is to compress these data in this case we process like this
If n ( n > 1) records in t1 have the same t1_info, and the same set of
info in both tables
t2 and t3 then we will delete cascade (n-1) rows from t1
e.g. :
t1 : t1_id t1_info
1 'car'
2 'car'
3 'car'
4 'van'
t2 : t2_id t2_info t2_t1_id
1 'tyre' 1
2 'brake' 1
3 'tyre' 2
4 'brake' 2
5 'tyre' 3
6 'brake' 3
7 'capacity' 4
t3 : t3_id t3_info t2_t1_id
1 'price' 1
2 'power' 1
3 'price' 2
4 'power' 2
5 'price 3
6 'power' 3
7 'power' 4
In this case we delete on cascade only t1_id = 2 and t1_id = 3 from
t1
I am writing the function and I have a big problem of performance,
You are helpful for each idea you give to me!
