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Web app for diffing the data in the database
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sequel_diff, database comparison web-based tool


sequel_diff allows you to compare contents of two database tables (or two sets of data from within the same table) or views, and see which rows differ, with some aggregation capability as well (declare some columns as “key” and other as “values”).


You should specify your database “connection url” editing the file itself. (One of TODOs are to move this elsewhere.)

Installation and starting

sequel_diff is sinatra-based app, so you will need sinatra installed, together with haml gem, which is used as template language:

gem install sinatra haml

You can then start the application from command line, doing:

ruby sequel_diff.rb

or as any other Rack-enabled web application.


  • Choose left and right table

  • Chose which fields will be part of the key, which fields will be values and which should be ignored

  • Optionally add constraints (WHERE part of SELECT statement) into the text area

  • Run the Diff


  • Move configuration elsewhere

  • Enable comparing tables from different databases

  • Enable separate constraints for left and right table

  • Improve documentation

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