Need assitance: Data load/Conversion Script

I have been tasked to create a data load script that will map a an ID already in an existing table to a new code within a field recently added to that table.

For example:

The current table has Business Unit and Site ID exiting. We added a new field to this table called Legal Entity. I need to update the table to pair up the existing Business Unit to its new Legal Entity.

The homework has already been done on pairing up the data and the values exist in a spreadsheet which can be exported out to a CSV or Tab Delimited file for me to read from.

If someone could give me a push in the right direction and maybe some sample code, I can defenitely pick it up from there.

Thank you

Use the UTL file to upload the existing csv file into the database into a temp table. The file has to be put into the database server foir the UTLK file to work
Else u can also use SQL loader if thats more convinient.
then use the temp table to update the legal entity values as required. Hope this helps