Feb 27, 2014 Removing Duplicates from MongoDB. Duplicate records can be removed from a MongoDB collection by creating a unique index on the collection and specifying the dropDups option. Assuming the collection includes a field named recordid that uniquely identifies a record in the collection, the command to use to create a unique index and drop duplicates is.
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If you've acquired some duplicates in MongoDB that you want to get rid of, from Michael Francis provides a how-to on cleaning them up. The best option, obviously, is not to duplicate things in the first place - you're welcome - but Francis' post is focused on solving the problem after the fact, and he explains some helpful techniques.The basic idea of Francis' strategy is to hash your documents to find duplicates and store them in a pair of arrays for easy disposal. He has some extra tips and shortcuts depending on how you're working with MongoDB - Node.js and Mongoose makes it easier - but the basics should translate pretty well from language to language.Check out Francis' and see if it can help you clean up your data.