How do i find difference of data between 2 tables & insert a flag based on

Question

I got a situation like.
My application is connecting to different database and getting data to our schema
using dblink.That data is stored into a temporary table.Every day a nightly job is executed and stores the latest data into temp table .we compare the data in temp table with master table.If it is new record insert into master,if the record does not exists delete it,if the record is modified update.
This is taking too long in production.
My idea is
First iam getting all data into temp table.temp table data is compared with master and getting only modified data(mismatch)into another temp table.i want to insert a flag like I for insert,d for delete and u fro update to this temp while comparing only.
please give some tips to resolve this issue.
or give me the best solution to improve its performance.
Thanks in advance
Looking forwrd to hear an immediate response

Answer 1

How do you compare two records? Is it by comparing only PK or UK fields or all the fields? The solution comparing PK's or UK's
TEMP_TBL table - tid is the PK
MASTER table - mid is the PK
update TEMP_TBL set flag='N';
update(select a.flag from TEMP_TBL a, MASTER b where a.tid=b.mid)
set a.flag='Y';
update(select a.flag from TEMP_TBL a, MASTER b where a.tid=b.mid(+) and a.flag='N') set a.flag='I';
-- Compare fields other than PK.
-- Update flag
update(select a.flag from TEMP_TBL a, MASTER b where a.tid=b.mid(+) and a.flag='N' and a.col1<>b.col1) set a.flag='U';