Book Image

Mastering Apex Programming

By : Paul Battisson
5 (1)
Book Image

Mastering Apex Programming

5 (1)
By: Paul Battisson

Overview of this book

As applications built on the Salesforce platform are now a key part of many organizations, developers are shifting focus to Apex, Salesforce’s proprietary programming language. As a Salesforce developer, it is important to understand the range of tools at your disposal, how and when to use them, and best practices for working with Apex. Mastering Apex Programming will help you explore the advanced features of Apex programming and guide you in delivering robust solutions that scale. This book starts by taking you through common Apex mistakes, debugging, exception handling, and testing. You'll then discover different asynchronous Apex programming options and develop custom Apex REST web services. The book shows you how to define and utilize Batch Apex, Queueable Apex, and Scheduled Apex using common scenarios before teaching you how to define, publish, and consume platform events and RESTful endpoints with Apex. Finally, you'll learn how to profile and improve the performance of your Apex application, including architecture trade-offs. With code examples used to facilitate discussion throughout, by the end of the book, you'll have developed the skills needed to build robust and scalable applications in Apex.
Table of Contents (21 chapters)
1
Section 1 – Triggers, Testing, and Security
8
Section 2 – Asynchronous Apex and Apex REST
15
Section 3 – Apex Performance

Improving query selectivity

When we run a SOQL query in Salesforce, the Force.com query optimizer processes the query and uses a set of statistics calculated in an ongoing fashion to determine the most efficient way to run the query against the underlying database. In order to achieve the best performance possible, we want to make our query as selective as possible to reduce the number of records returned. This has a number of beneficial effects on our performance. Firstly, the query will run faster than it would do if not selective, which will reduce the running time perceived by our end user. Secondly, it will reduce the amount of data returned for us to process or display, thereby improving the performance of the rest of our code. Thirdly, it will mean we have retrieved a smaller number of rows contributing to the query rows governor limit.

So, what makes a query selective? The first thing that indicates selectivity is whether the field is indexed. The following types of field...