Mongo DB serves as a back-end to Explorer. All the transaction in blockchain is also stored in Mongo DB. MongoDB is a free and open-source NoSQL document database used commonly in modern web applications. This tutorial will help you set up MongoDB.
sudo apt-get update
sudo apt-get install -y mongodb-org
To install a specific release, you must specify each component package individually along with the version number, as in the following example:
sudo apt-get install -y mongodb-org=3.6.0 mongodb-org-server=3.6.0
mongodb-org-shell=3.6.0 mongodb-org-mongos=3.6.0 mongodb-org-tools=3.6.0
sudo service mongod start
Once Mongo DB is installed we need to create the database which will be by iquidus explorer and set up the credentials for that.