We have given a file which contains some records (no of records might be in lakhs). Now problem is we have to read the data from this file and then query the database using the data from file. Finally we'd export the data in CSV.
What could be the best way so that we can do this very quick and it should be memory efficient also.
I've been told before but I forget, what is a lakh?
Usually the best tool for bulk data manipulation is the one supplied with your database, since it will usually allow you to make all sorts of tweeks to aid performance. Which database are you using?