Thanks Ora 777,

The website you provide it is really helpful, but if you see my original post, what I need to load Header, Detail and Trailer data. Now the confusion is do I have to create 3 tables one for header, one for Detail and one for Trailer
OR
Do I have to create only 1 table but if one table than the content of Header,Detail and Trailer are totally different with each other? This is point where I am confused. Sounds like should I create 3 table and using the conditional SQL*Loader I will load Header data from flat file into Header table, Detail data into Detail table and trailer data into Trailer table, But if this is the case how I can check/condition for Header, Detail and Trailer.
Example of flat file:

HSONY INC062102
D001ABC
D002MNG
D003GKI
D004KLM
T00901287A

First line is Header start with H, Detail lines start with D and Trailer data start with T. (Each line start with tag H, D and T)

Once again I need help to resolve the issue. Thanks in advance.

Regards.