Perform Lookup File In Perl From One input File

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# 1  
Old 08-03-2011
Perform Lookup File In Perl From One input File

Hi Perl Guru,

I'm new to Perl Programming & need some help.

I need to have some kind of similar code template so I can start to work on it.
I'm been reading some forums and did not find anything that are similar so I start to work on it. I've been struggling on how to start it.

Any help will be greatly appreciated.

Below are the 2 samples input files, 1 sample output file
& pseudo code logic.

File A, input file , '~' delimiter
column heading


File B, input validation file (this is for lookup file ), '~' delimiter
column heading

5~ClientCharacterSet~(UTF8, ASCII)~match_any_in_list~E~

I think I will have 2 loops

1st loop will be outer loop which read in the File A until eof

For each record in File A

I need to have a inner loop to perform a lookup against rows in the File B

Here are the logic to perform lookup.

2 lookup keys are object type & object name columns for both files
  once keys matched 
   then check match_method column from File B

    if match_method = 'must_match_exact' 
     then compare  where FileA.object_values == FileB.object_values 
        if not equal 
           then write to output file
        else next

    elsif match_method = 'must_match_pattern' 
     then compare  where FileA.object_values pattern match defined in FileB.object_values 
        if not equal 
           then write to output file
        else next
    elsif match_method = 'match_any_in_list' 
     then compare  where FileA.object_values match any values defined in FileB.object_values 
        if not equal 
           then write to output file
        else next

    else exit the inner loop and read the next record from File A until eof

Output file layout as below
'File A ' all collumns from File A ' ==> ' File B ' then all columns from File B

So the result is the 4th row from the input file A that is failed the validation

File A '5~Variant~8 ==> File B 5~Variant~12~must_match_exact~E~

Last edited by pludi; 08-03-2011 at 05:22 AM..
# 2  
Old 08-03-2011
Well, the problem is a classic join. The first two fields combined are a key, and the next two are the validation payload or to be validated payload. You can either put the smaller set in a string addressed array / a hash map for fast lookup, or disassemble, labeling for line #, sort both files' data by key and merge them, doing all of each validation at once. You can resort the errors by line number, and who will know!

We get this question regularly in various forms. It is important to see it as a classic join problem, just as in an RDBMS. In fact, loading/applying it all to a DRBMS tool means you can solve most of it in SQL.
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