Ane dapet tugas project dari kampus bikin database.
Nah udh hampir selesai sih
Tapi stuck di pembuatan table subtype disjoint

Contohnya gini
ID | merek | size
========
1 | Monitor1 | 17 inch
2 | Monitor2 | 22 inch

Table 2
ID | Merek | Speed
==================
3 | Harddisk1 | 7200rpm
4 | Harddisk2 | 5400rpm

ntar hasil tabel gini
ID | Merel | Size | Speed
==================
1 | Monitor1 | 17 inch | (null)
2 | Monitor2 | 22 inch | (null)
3 | Harddisk1 | (null) | 7200rpm
4 | Harddisk2 | (null) | 5400rpm

Query nya gmn ya gan?
Ane nyoba yang null mesti keisi terus berulangu-ulang gitu
ID | Merel | Size | Speed
==================
1 | Monitor1 | 17 inch | 7200rpm
2 | Monitor2 | 22 inch | 5400rpm
3 | Harddisk1 | 17 inch | 7200rpm
4 | Harddisk2 | 22 inch | 5400rpm

Makasi gan