# Writing to database row based on column name with FasterCSV **URL:** \ **Category:** Ruby\ **Created:** [February 2, 2010, 8:22pm UTC](https://www.ruby-forum.com/t/writing-to-database-row-based-on-column-name-with-fastercsv/182790 "2010-02-02T20:22:39Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![jmaenpaa](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/9de053/32.png) [@jmaenpaa](https://www.ruby-forum.com/u/jmaenpaa)\ **Post date:** [February 2, 2010, 8:22pm UTC](https://www.ruby-forum.com/t/writing-to-database-row-based-on-column-name-with-fastercsv/182790/1 "2010-02-02T20:22:39Z")
Hello all, I’ve added a couple new columns to a database table. I was trying to add default data as the .csv file is being read into the table. I’m not sure on how to do this. - import\_irb\_file - def import\_irb\_file # set file name file = params[:irb][:file] deletecount = 0 rowcount = 0 # delete all irb records @irb = Irb.find(:all, :conditions =\> “reconciled = 1”) @irb.each { |i| i.destroy deletecount+=1 } Irb.transaction do FasterCSV.parse(file, :headers =\> true, :header\_converters =\> lambda { |h| h.tr(" ", “_").delete("^a-zA-Z0-9_”)}, :converters =\> :all ) do |row| Irb.create!(row.to\_hash) rowcount += 1 end end # if successful then display, then redirect to index page flash[:notice] = “Successfully deleted #{deletecount} and added #{rowcount} IRB record(s).” redirect\_to :action =\> :index ``` rescue => exception file_name = params[:irb]['file'].original_filename file_parts = params[:irb]['file'].original_filename.split('.') ext = file_parts[1] if ext != 'csv' error = "CSV file is required" else error = ERB::Util.h(exception.to_s) # get the error and HTML ``` escape it end # If an exception in thrown, the transaction rolls back and we end up in this # rescue block ``` flash[:error] = "Error adding projects to IRB table. (#{error}). ``` Please try again." ``` redirect_to :controller => 'irbs', :action => 'new' ``` end Thank you for any and all help with this. JohnM ---
**Author:** ![jmaenpaa](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/9de053/32.png) [@jmaenpaa](https://www.ruby-forum.com/u/jmaenpaa)\ **Post date:** [February 2, 2010, 8:31pm UTC](https://www.ruby-forum.com/t/writing-to-database-row-based-on-column-name-with-fastercsv/182790/2 "2010-02-02T20:31:58Z")
On Feb 2, 2010, at 1:22 PM, John M. wrote: > I’ve added a couple new columns to a database table. I was trying to > add default data as the .csv file is being read into the table. I’m not > sure on how to do this. > Thank you for any and all help with this. I’m happy to try and help, but I’m not sure I understand the question. What are you trying to do? James Edward G. II ---
**Author:** ![jmaenpaa](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/9de053/32.png) [@jmaenpaa](https://www.ruby-forum.com/u/jmaenpaa)\ **Post date:** [February 2, 2010, 8:42pm UTC](https://www.ruby-forum.com/t/writing-to-database-row-based-on-column-name-with-fastercsv/182790/3 "2010-02-02T20:42:28Z")
Thanks James for the reply. I need to add default values (0) to 2 columns that are not in the csv. For example, ``` Column 1, Column 2, New Column 1, New Column 2 --------- --------- ------------- ------------ ``` Row 1 csv value csv value 0 0 When I go to create a row, I want to check for these column headers and write to the table with a zero. I’m not sure if it’s easier to write to the csv first, adding the columns, then parsing to the database or just do it all at once. John ---
**Author:** ![jmaenpaa](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/9de053/32.png) [@jmaenpaa](https://www.ruby-forum.com/u/jmaenpaa)\ **Post date:** [February 2, 2010, 9:06pm UTC](https://www.ruby-forum.com/t/writing-to-database-row-based-on-column-name-with-fastercsv/182790/4 "2010-02-02T21:06:31Z")
On Feb 2, 2010, at 1:42 PM, John M. wrote: > write to the table with a zero. > How about changing this code: Irb.create!(row.to\_hash) to: Irb.create!( { “New Column 1” =\> 0, “New Column 2” =\> 0 }.merge(row.to\_hash) ) Does that do what you wanted? James Edward G. II ---
**Author:** ![jmaenpaa](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/9de053/32.png) [@jmaenpaa](https://www.ruby-forum.com/u/jmaenpaa)\ **Post date:** [February 2, 2010, 9:19pm UTC](https://www.ruby-forum.com/t/writing-to-database-row-based-on-column-name-with-fastercsv/182790/5 "2010-02-02T21:19:09Z")
Yes, Thank you James for your expertise. Just a question to understand. Using the .merge method, does this do the actual insert of the new column data? or does it take the data and “merge” it into the csv before the insert? Is this in Ruby? I noticed it’s not in the FasterCSV docs. > Irb.create!( { “New Column 1” =\> 0, > “New Column 2” =\> 0 }.merge(row.to\_hash) ) Thanks again. John ---
**Author:** ![jmaenpaa](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/9de053/32.png) [@jmaenpaa](https://www.ruby-forum.com/u/jmaenpaa)\ **Post date:** [February 2, 2010, 9:27pm UTC](https://www.ruby-forum.com/t/writing-to-database-row-based-on-column-name-with-fastercsv/182790/6 "2010-02-02T21:27:44Z")
On Feb 2, 2010, at 2:19 PM, John M. wrote: > Using the .merge method, does this do the actual insert of the new > column data? or does it take the data and “merge” it into the csv before > the insert? > Is this in Ruby? I noticed it’s not in the FasterCSV docs. merge() is just Hash#merge() from Ruby, yes. It doesn’t change the file, no. It just changes the data read before it is handed off to ActiveRecord. James Edward G. II ---
**Author:** ![jmaenpaa](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/9de053/32.png) [@jmaenpaa](https://www.ruby-forum.com/u/jmaenpaa)\ **Post date:** [February 2, 2010, 9:27pm UTC](https://www.ruby-forum.com/t/writing-to-database-row-based-on-column-name-with-fastercsv/182790/7 "2010-02-02T21:27:21Z")
Well, if I’d do a little detective work, I’d notice that I’m working with Hashes. Therefore, the “Hash” class. John