Book Image

Graph Data Processing with Cypher

By : Ravindranatha Anthapu
Book Image

Graph Data Processing with Cypher

By: Ravindranatha Anthapu

Overview of this book

While it is easy to learn and understand the Cypher declarative language for querying graph databases, it can be very difficult to master it. As graph databases are becoming more mainstream, there is a dearth of content and guidance for developers to leverage database capabilities fully. This book fills the information gap by describing graph traversal patterns in a simple and readable way. This book provides a guided tour of Cypher from understanding the syntax, building a graph data model, and loading the data into graphs to building queries and profiling the queries for best performance. It introduces APOC utilities that can augment Cypher queries to build complex queries. You’ll also be introduced to visualization tools such as Bloom to get the most out of the graph when presenting the results to the end users. After having worked through this book, you’ll have become a seasoned Cypher query developer with a good understanding of the query language and how to use it for the best performance.
Table of Contents (18 chapters)
1
Part 1: Cypher Introduction
4
Part 2: Working with Cypher
9
Part 3: Advanced Cypher Concepts

Working with the CASE clause

The CASE clause is an expression constructed that is used to transform results. There are two different forms of CASE expression and they are as follows:

  • A simple CASE form to compare against multiple values
  • A generic CASE form to express multiple conditional expressions

We will take a look at the simple CASE expression first.

Working with simple CASE expressions

In simple CASE expressions, the expression is evaluated and compared to the WHEN clauses. The corresponding expression is then evaluated and the resulting value is returned. If no value is found, the ELSE clause expression is evaluated and the corresponding value is returned. If there is no ELSE clause, then a null value is returned.

The syntactic representation of this looks like this:

CASE test
  WHEN value THEN result
  [WHEN ...]
  [ELSE default]
END

We can see from this syntax that the first CASE expression is evaluated and its...