Hasan Savran shows off a new feature in Cosmos DB:
A computed property is a virtual property that is not physically stored in a document. You can use data from other properties of a document to calculate a value for the computed property. This will help you to save CPU power since the database engine does not need to calculate the computed column value for each query request. In the Cloud CPU power means money! Computed Columns are like coupons you can use to save money.
Read on to learn more about how computed properties work, their limitations, and some examples of how to create and use them.