Book Image

Mastering RethinkDB

By : Shaikh
Book Image

Mastering RethinkDB

By: Shaikh

Overview of this book

RethinkDB has a lot of cool things to be excited about: ReQL (its readable,highly-functional syntax), cluster management, primitives for 21st century applications, and change-feeds. This book starts with a brief overview of the RethinkDB architecture and data modeling, and coverage of the advanced ReQL queries to work with JSON documents. Then, you will quickly jump to implementing these concepts in real-world scenarios, by building real-time applications on polling, data synchronization, share market, and the geospatial domain using RethinkDB and Node.js. You will also see how to tweak RethinkDB's capabilities to ensure faster data processing by exploring the sharding and replication techniques in depth. Then, we will take you through the more advanced administration tasks as well as show you the various deployment techniques using PaaS, Docker, and Compose. By the time you have finished reading this book, you would have taken your knowledge of RethinkDB to the next level, and will be able to use the concepts in RethinkDB to develop efficient, real-time applications with ease.
Table of Contents (16 chapters)
Mastering RethinkDB
Credits
About the Author
About the Reviewer
www.PacktPub.com
Preface

Performing conditional queries


ReQL supports conditional queries using subqueries, expressions, and the lambda function. In this section, we will look at each one of them using sample code written in Node.js.

In order to perform these queries, I have populated our users table in the test database with some documents. Here is the query executed from the RethinkDB web administrative screen:

r.db('test').table('users').insert([{ 
name : "John", 
age : 24 
}, { 
name : "Mary", 
age : 32 
},{ 
name : "Michael", 
age : 28 
}]) 

Note

In the web administrative screen, you do not need to provide the run function with a connection; it automatically appends and executes the query on the server.

Let us run a query to find out documents with an age greater than 30 years. We are going to execute the following code after getting a connection to the database, the same as we did in the former section:

rethinkdb.table('users').filter(function (user) {  
return...