How to compare two csv files line by line in apachi nifi flow file using groovy script

Question

I have once scenario in apachi nifi, that is i have a csv data in the flow file and i have the some csv data in my database which has some different data than the csv flow file, now i want to compare both csv files(flow file content from my nifi flow file and ,csv data which i read from database) using groovy script, could you please help me how can i achieve this using nifi. I have my data like below.

existing content(123_456.csv) from db
    

A   3000    AAA008
A   3001    AAA008
A   3002    AAA008
A   3003    AAA008
A   3005    AAA008
A   3006    AAA008
A   3007    AAA008
A   3008    AAA008
A   3009    AAA008
A   3010    AAA008
A   3011    AAA008
A   3012    AAA008(This record is deleted in the new file from the flow file, so i dont need to consider this from the new file)



 Flow file content(123_456.csv) from apachi nifi flow file
    
A   3000    AAA008
A   3001    AAA008
U   3002    AAA009(This I need to update, since the third Colum is changed)
A   3003    AAA008
I   3013    AAA113(This I need to insert ,since I don't have this in the old file from the db)
A   3005    AAA008
A   3006    AAA008
A   3007    AAA008
A   3008    AAA008
A   3009    AAA008
A   3010    AAA008
A   3011    AAA008

Could you please help me with the groovy script, to achieve this. Thank you

Answer 1

Create 2 lists A & B Create 2 Sets A-match & A-nonmatch Create 2 Sets B-match & B-nonmatch

Then loop through A matching up to B - Add matches to A-match Add non-matches to A-nonmatch Then loop through B matching up to A - Add matches to B-match Add non-matches to B-nonmatch

Now you have a sets of matches from A to B nonmatches from A to B matches from B to A nonmatches from B to A