title: ElasticSearch vs Relational Database
body: <p>I'm creating a microservice to handle the contacts that are created in the software. I'll need to create contacts and also search if a contact exists based on some information (name, last name, email, phone number). The idea is the following: 
  A customer calls, if it doesn't exist we create the contact asking all his personal information. The second time he calls, we will search coincidences by name, last name, email, to detect that the contact already exists in our DB.
  What I thought is to use a MongoDB as primary storage and use ElasticSearch to perform the query, but I don't know if there is really a big difference between this and querying in a common relational database.</p>
  
  <p>EDIT: Imagine a call center that is getting calls all the time from mostly different people, and we want to search fast (by name, email, last name) if that person it's in our DB, wouldn't ElasticSearch be good for this?</p>