Saving Data on Android

6
Chapter 6: En/ty 
Defini/ons
By Aldo Olivares
In the previous chapter, you learned the architecture behind Room. You also learned 
about ORMs, Jetpack Architecture Components and the advantages and 
disadvantages of SQLite.
In this chapter, you'll cover all you need to know about Room entities. Along the way, 
you will learn:
• The properties of SQLite tables.
• How to add Room's dependencies to your gradle files.
• How to create SQLite tables using Room annotations.
• How to define primary keys and column names.
I hope you're ready to get started!
Note
: This chapter assumes you have a basic knowledge of Kotlin and Android. 
If you’re new to Android, you can find a lot of beginner Android content to get 
you started on our site at 
https://www.raywenderlich.com/category/android
. If 
you know Android, but are unfamiliar with Kotlin, take a look at our tutorial, 
"Kotlin for Android: An Introduction" at 
https://www.raywenderlich.com/
174395/kotlin-for-android-an-introduction-2
.
raywenderlich.com
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GeTng started
Have you ever played trivia games and thought, "There should be a game like this but 
with questions for Android developers"? Well, the sample app you will be working 
on, 
DroidQuiz
, is a trivia game that allows you to answer a series of questions to test 
your knowledge of Android.
In this chapter, you're only going to build entities that represent the tables of your 
database. If you've had some previous experience with SQL, you probably know that 
this can be somewhat annoying or painstaking to accomplish. Additionally, in 
"Chapter 3, SQLite Database," you saw how, with SQL syntax, it can sometimes be 
hard to deduce which parts of it caused an error (if by some chance you get one). The 
Room database, and its