NoSQL (Not only Structured Query Language) databases are called as non-relational or unstructured databases. These databases are open source databases. Basically horizontally scalable feature is useful in most of the cloud computing applications. These are to be able to store and process mass data effectively. Traditional relational databases are facing many problems in solving mass data storage and retrieving due to their structured schema. Unstructured databases do not follow the specific schema structure. This survey will realize the necessity in moving towards NoSQL databases.