From: Stephen Beckman <bec04015@...>
Date: 2011-11-19T05:59:50+09:00
Subject: Trouble comparing a NULL in Ruby

Hey folks,

I am currently writing a script that functions as follows:

It will first open up a connection to our local database and run a SQL
script I have written in, then create an excel file based off of that
SQL query.  From that point it will sit until changes have potentially
been made in the database.  At that point the excel file that had been
made and then saved off will be called again as a master record to
compare to the same SQL query and new excel file which will be created.
I have it written so that from the command prompt one would simply call
the .rb script, state whether the master record is being created or
there is a check being made to a previously made excel file and what the
name of that file is.  This is where my problem enters in, is that if
there are blanks in the master file, as in nothing in the field in
either the SQL query and thereby in the excel file, it chokes and won't
fire if there is a legitimate input in a later file.

Let me illustrate:

"" == "foo"

would pass back true.

Perhaps this is a problem with the Spreadsheet gem that I am using and
in that case this is an inappropriate place to ask for assistance, if
so, my apologies.  The code in question has been attached.

I have tried several different things, including using '.empty',
'.nil?', and what is written there now in an attempt to have it either
write it as 'NULL' when creating the master sheet, or to catch it when
making a check as it is written.

I feel like the way to solve this is to have it catch the empty cells
when it is being parsed, but I haven't been able to do that yet, and the
reason why I am asking.

Thanks in advance!

Attachments:
http://www.ruby-forum.com/attachment/6755/newbill.rb


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