Saving Data on Android

changed
.
• You should avoid 
dropping the database
 if it changes, and try to 
migrate
 the 
structure between versions.
• Every database consists of the four standard operations - 
Create
, 
Read
, 
Update
, 
and 
Delete
, or 
CRUD
 for short.
• To help you avoid so much 
SQL
 code, and to simplify the operations, Android 
utilizes the 
SQLiteOpenHelper
.
Saving Data on Android
Chapter 3: SQLite Database
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• To store data for operations, the SQLiteOpenHelper uses 
ContentValues
.
•
ContentValues
 are just a key-value pair structure, just like a Map, which is used to 
insert or update data in the database.
• You can inspect the database by copying it from the 
Device File Explorer
, and 
opening it with a tool, like the 
SQLite Browser
 or 
DB Browser
.
• It is a good practice to write some 
Unit tests
 for your database, to be sure 
everything works as expected, 
without running the application
.
Where to go from here?
If you would like to know more about SQLite and the syntax that makes up SQLite 
queries, a more in-depth guide for SQLite can be found in SQLite's Language Guide, 
which you can access here: 
https://sqlite.org/lang.html
.
This "Unit Testing with Robolectric" article is also an interesting guide about how 
using Robolectric with Android, which you can read here: 
https://github.com/
codepath/android_guides/wiki/Unit-Testing-with-Robolectric
.
Saving Data on Android
Chapter 3: SQLite Database
raywenderlich.com
71

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