One of the nice and interesting features in Mongo is automatically expiring data in the collection after a predetermined amount of time. This is a very useful tool when we desire to purge some data older than a particular timeframe. For a relational database, it is not common for folks to set up a batch job that runs every night to perform this operation.
With the Time To Live (TTL) feature of Mongo, we need not worry about this as the database takes care of it out-of-the-box. Let's see how we can achieve this.
Let's create some data in Mongo that we want to play with using the TTL indexes. We will create a collection called ttlTest for this purpose. We will require a server to be up and running. Refer to the Single node installation of MongoDB recipe in Chapter 1, Installing and Starting the MongoDB Server, to learn how to start the server. Also, start the shell with the TTLData.js script loaded. This script will be...