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Adhar is an excellent example of real world use cases of MongoDB.
India’s Unique Identification project, aka Aadhar, is the world’s biggest biometrics database. Aadhar is in the process of capturing demographic and biometric data of over 1.2 billion residents.
Aadhar has used MongoDB as one of its databases to store this huge amount of data. MongoDB was among several database products, apart from MySQL, Hadoop and HBase, originally procured for running the database search. Here, MySQL is used for storing demographic data and MongoDB is used to store images.
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