I have a CSV file which contains an ID and several other columns. I also have a table in oracle where the ID identifies a row. How can I best replace the values that are in
Look at EXTERNAL TABLES in the Oracle doc. You can copy the csv file onto the Oracle server box and get Oracle to present it as a "normal" table on which you can run queries.
Then the problem just becomes one of copying data from one table to another.
External tables are really very useful for handling data loads like this.