Lets suppose that we have a database with three tables:
R(A',B,C): 100.000 records, r=100 bytes/record, bfr(R)=40 records/block, B(R)=2.500 blocks
S(B',D,E): 1.000 records, r=200 bytes/record, bfr(S)= 20 records/block, B(S)=50 blocks
T(C'F,G): 1.000 records, r=200 bytes/record, bfr(T)= 20 records/block, B(T)=50 blocks
R:Heap-organized
S:Sequential Organized
T:Sequential Organized
No indexes are available!
Question:
How can I calculate the cost for checking the consistency of the primary key and foreign key in table R for an INSERT command? Will I simply have to read the table 'till the end with
COST1 = B(R) Primary Key Consistency Constraint
COST2 = B(S)/2 Foreign Key Consistency Constraint
or is there any other way the system could check that itself?