In this document, we will see how to develop an appli which will allow a company to know which clients it did not call yet. This appli will show the business developer of the company which clients to call. To create the database, we use Firebase. More precisely, we use Firebase Realtime Database, which is a real-time database. Firebase Realtime Datatbase provides application developers an API that allows application data to be synchronized across clients and stored on Firebase's cloud (https://en.wikipedia.org/wiki/Firebase)
We create a Realtime Database on Firebase, in which we integrate the data about the clients. In the database, we first put the name of the company, and then the name of the company's manager and the number of times he or she was called by phone by the business developer. On the following image, there is an example of a dataset with several clients.
Then, we create a file on Glitch. Glitch is In this file, we put the Firebase SDK Snippet of the project. Then we write a query to find all the clients with their property "numbercalls" equal to 0.