Running the aggregation using only the $group pipeline operator, we'll get something like the following below from the MongoDB shell.A document is the basic unit of data in MongoDB. The key CERT within _id can have any name. In this case, we are grouping together the CERT numbers so $CERT is used to point to the CERT field. We'll need an _id field first, which is mandatory because it indicates what we are grouping by. The $group operator is the first one we want to use, and we want to set it up so it groups our documents by the CERT number. The aggregate function takes an array of aggregation operators. We'll apply the aggregate function to our list like this: db.list.aggregate() Let's start out with how to use the aggregate method in MongoDB. For a closer look at MongoDB's aggregation pipeline operators see the article Aggregations in MongoDB by Example. You can find duplicate values within your MongoDB database using the aggregate method along with the $group and $match aggregation pipeline operators. Now, let's start looking for duplicate banks in our dataset using MongoDB's aggregation pipeline operators. We won't be looking for duplicate Bank Names since a bank can have multiple branches and have the same name. The CERT number is the number that we'll be using to identify duplicate banks. The CERT number is unique to each branch of a bank. "Acquiring Institution" : "State Bank of Texas",Įach document is provided with a unique ObjectId by MongoDB and also a unique CERT number provided by the FDIC. "Bank Name" : "Seaway Bank and Trust Company", In the MongoDB shell, our data should look similar to this: db.list.findOne() Now, let's log into our MongoDB shell and look at our documents. One you've run mongoimport in the terminal, you should see that 559 documents have been successfully imported into your database. mongoimport -host aws-us-west-2-portal.0. -port 99999 -db banks -collection list -ssl -sslAllowInvalidCertificates -u user -p mypass -type csv -headerline -file banklist.csv Make sure to use the credentials for your deployment. To insert the CSV file, we'll be using mongoimport to create a database called banks and a collection called list. We've altered the list for this article to include duplicate banks, so our list now includes 559 banks which can be downloaded here.Īfter downloading the CSV file, let's import the file into our Compose MongoDB deployment. The dataset that we will be using is a CSV file containing a list of 550 failed banks compiled by the Federal Deposit Insurance Corporation (FDIC). In other words, MongoDB lets you select fields and group together documents based on your selection in order to find duplicate documents. MongoDB's aggregation pipeline makes finding duplicate documents easier by allowing you to customize how documents are grouped together and filtered. Need to find duplicate documents in your MongoDB database? This article will show you how to find duplicate documents in your existing database using MongoDB's aggregation pipeline.įinding duplicate values in your database can be difficult, especially if you have millions of documents to look at. Finding Duplicate Documents in MongoDB mongodb aggregation deduplication Free 30 Day Trial
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