Best practice for deleting data based on mismatch

Question

I have two tables which share the same key columns (one is an extension table of the other, basically)
INVPARTINSTOCK_C is current data
INVPARTINSTOCK_D is a date extension table
I want to remove all data in D which is not in C
I can gather a list of mismatched data by using:
select
d.Contract,
d.Part_No,
d.Location_No,
d.Lot_Batch_No,
d.Serial_No,
d.Eng_Chg_Level
from invpartinstock_d d
MINUS
select
c.Contract,
c.Part_No,
c.Location_No,
c.Lot_Batch_No,
c.Serial_No,
c.Eng_Chg_Level
from invpartinstock_c c but how do I apply that to a DELETE FROM INVPARTINSTOCK_D WHERE... ?
Thanks

Answer 1

1) It depends on, at least, the data volumes we're talking about, but
DELETE FROM dtable
  WHERE (column_list) IN (your_minus_query)should be functionally correct. Probably more efficient would be
DELETE FROM invpartinstock_d d
WHERE NOT EXISTS(
    SELECT 1
      FROM invpartinstock_c c
     WHERE c.contract = d.contract
    )2) Why isn't there a foreign key relationship that prevents this sort of mismatch in the first place?
Justin