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Learn Scala Programming

You're reading from   Learn Scala Programming A comprehensive guide covering functional and reactive programming with Scala 2.13, Akka, and Lagom

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Product type Paperback
Published in Oct 2018
Publisher Packt
ISBN-13 9781788836302
Length 498 pages
Edition 1st Edition
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Author (1):
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Slava Schmidt Slava Schmidt
Author Profile Icon Slava Schmidt
Slava Schmidt
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Table of Contents (19) Chapters Close

Preface 1. An Introduction to Scala 2.13 2. Understanding Types in Scala FREE CHAPTER 3. Deep Dive into Functions 4. Getting to Know Implicits and Type Classes 5. Property-Based Testing in Scala 6. Exploring Built-In Effects 7. Understanding Algebraic Structures 8. Dealing with Effects 9. Familiarizing Yourself with Basic Monads 10. A Look at Monad Transformers and Free Monad 11. An Introduction to the Akka and Actor Models 12. Building Reactive Applications with Akka Typed 13. Basics of Akka Streams 14. Project 1 - Building Microservices with Scala 15. Project 2 - Building Microservices with Lagom 16. Preparing the Environment and Running Code Samples 17. Assessments 18. Other Books You May Enjoy

Chapter 14

  1. What is a database migration?

The database migration (or schema migration) is the automatic management of updates to the database schema. The changes to the schema are incremental, usually reversible, and applied in the moment the database schema needs to be changed in order to reflect changes in the application code.

  1. Describe what could be an alternative approach to discarding an order completely, in the case of insufficient stock for some articles?

One of the alternatives could be to satisfy orders for all articles for which there are sufficient stock. This could be implemented by running each inventory update in a separate transaction and combining the results of all of them that succeeded.

Yet another alternative would be to satisfy orders as fully as possible. This approach would require selecting rows for update, calculating new possible states, and applying...

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