The document provides information about an Android Academy event on data integration. It includes an agenda that covers databases, SQLite, and content providers. It also includes sample SQL queries and explanations of CRUD operations. The document demonstrates how to use a SQLiteOpenHelper to simplify database management in Android.

1. Android Academy TLV
4/12/2016
Britt Barak
WIFI: pUp3EkaP
Content Providing
#5

2. First,

3. Britt Barak
Britt Barak
Figure 8
Android Academy
Women Techmakers

4. Jonathan Yarkoni
Android Developer & Advocate
Ironsource
Android Academy Staff
Yonatan Levin
Google Developer Expert &
Android @ Gett
Britt Barak
Android Lead
Figure8
Yossi Segev
Android Developer
Crave

5. Largest Android Community
Android Academy - TLV
TLV - Android Academy
~ 2000 members Join Us:

6. What Do We Do?
●Android Fundamentals
●Android UI / UX
●Community Hackathon
●Android Performance
●Mentors Program

7. Community Mentors
Erez Pickman

8. Data In Apps

10. Application
Content Provider
Database (SQLite)
Road Map

11. Road Map
Last time:
Activity Life
Cycle
Today:
Data
Integration
Next time:
Load Data To
Activity

12. Database

13. Database
Database:
A structured set of data
Relational database:
A Database which uses tables and relations to organize the data,
Usually uses SQL for operations
Relational Database management system:
A program (or less) that implements a Relational Database.
Common vendors:PostgreSQL, Oracle, MySQL, Microsoft SQL Server

14. When to use a Database
- Large datasets
- Structured data
- Cache / Preload data
Better loading times, Better battery utilization

15. Our Database
SQLite is a mini-RDBMS.
Unlike most:
- Serverless (Runs in your process, not on its own)
- Zero-Configuration
- Most widely deployed database
Get to know it better: https://www.sqlite.org/

16. Our Database
Most widely deployed database:
Every Android device
Every iPhone and iOS device
Every Mac
Every Windows 10 machine
Every Firefox, Chrome, and Safari web browser
Every instance of Skype
Every instance of iTunes
Every Dropbox client
Most television sets and set-top cable boxes
Most automotive multimedia systems
Countless millions of other applications
Source: https://www.sqlite.org/mostdeployed.html

17. SQL - Structured Query Language
the language to
communicate with database.

18. Consider this table
Data taken from: http://www.meetup.com/TLV-Android-Academy/events/ ☺
* Not really how dates are represented
_ID Date* Title Lecturer Floor
1 1/11 Intro And Basics Yonatan 29
2 8/11 Basics and ListViews Britt 29
3 13/11 Off threading Yarkoni 34
4 20/11 New Activities and Intents Yonatan 34
5 27/11 Lifecycles Yarkoni 34
6 4/12 Databases and stuff Britt Unknown
7 11/12 Loaders Yossi Unknown

19. Actions:
- Select - gets part of the table
- Update - modifies values in existing records
- Insert - Adds records to tables.
- Delete - Removes records from tables.

20. Select - gets part of the table
SELECT ( * | [column, column])
FROM (table)
WHERE (condition)
ORDER BY (column) (ASC | DESC)
This is uber-simplified. Read more: https://www.sqlite.org/lang_select.html

21. Select
SELECT *
FROM Sessions
WHERE floor=’34’
_ID Date* Title Lecturer Floor
3 13/11 Off threading Yarkoni 34
4 20/11 New Activities and Intents Yonatan 34
5 27/11 Lifecycles Yarkoni 34

22. Select
SELECT Date, Title
FROM Sessions
WHERE floor=’34’
Date* Title
13/11 Off threading
20/11 New Activities and Intents
27/11 Lifecycles

23. Select
SELECT Date, Title
FROM Sessions
WHERE floor=’34’
ORDER BY date DESC
Date* Title
27/11 Lifecycles
20/11 New Activities and Intents
13/11 Off threading

24. Select
SELECT *
FROM Sessions
WHERE title LIKE ’% and %’
_ID Date* Title Lecturer Floor
1 1/11 Intro and Basics Yonatan 29
2 8/11 Basics and ListViews Britt 29
4 20/11 New Activities and Intents Yonatan 34
6 4/12 Databases and stuff Britt Unknown

25. Select
SELECT *
FROM Sessions
WHERE lecturer LIKE ’Yo%’
_ID Date* Title Lecturer Floor
1 1/11 Intro And Basics Yonatan 29
4 20/11 New Activities and Intents Yonatan 34
7 11/12 Loaders Yossi Unknown

26. Select
SELECT *
FROM Sessions
WHERE lecturer LIKE ’Yo%’
AND floor = ‘34’
_ID Date* Title Lecturer Floor
4 20/11 New Activities and Intents Yonatan 34

27. Select
SELECT * FROM Sessions
_ID Date* Title Lecturer Floor
1 1/11 Intro And Basics Yonatan 29
2 8/11 Basics and ListViews Britt 29
3 13/11 Off threading Yarkoni 34
4 20/11 New Activities and Intents Yonatan 34
5 27/11 Lifecycles Yarkoni 34
6 4/12 Databases and stuff Britt Unknown
7 11/12 Loaders Yossi Unknown

28. UPDATE (table)
SET (column)=(expr) [, (column)=(expr) [,...]
WHERE (condition)
Update - Modifies values in existing records.
Again, Super simplified. Read more: https://www.sqlite.org/lang_update.html

29. UPDATE Sessions
SET lecturer=’Britt’, floor=29
WHERE _id = 6
Update
_ID Date* Title Lecturer Floor
6 4/12 Databases and stuff NULL NULL
_ID Date* Title Lecturer Floor
6 4/12 Databases and stuff Britt 29

30. INSERT INTO (table)
((column) [, (column) [,...]])
VALUES
( expr [, expr [,...]])
Insert - Adds records to tables
Read more: https://www.sqlite.org/lang_insert.html

31. INSERT INTO Sessions
(date, title, lecturer, floor)
VALUES
(‘18/12’, ‘Rich and responsive layout’,
null, null)
Inserting Data: Insert

32. Inserting Data: Insert
_ID Date* Title Lecturer Floor
1 1/11 Intro And Basics Yonatan 29
2 8/11 Basics and ListViews Britt 29
3 13/11 Off threading Yarkoni 34
4 20/11 New Activities and Intents Yonatan 34
5 27/11 Lifecycles Yarkoni 34
6 4/12 Databases and stuff Britt 29
7 11/12 Loaders Yossi Unknown
8 18/12 Rich and responsive layouts null null

33. Delete - Removes records from tables.
DELETE FROM (table)
WHERE (condition)

34. Deleting Data: Delete
DELETE FROM Sessions
WHERE floor = 29
_ID Date* Title Lecturer Floor
1 1/11 Intro And Basics Yonatan 29
2 8/11 Basics and ListViews Britt 29
3 13/11 Off threading Yarkoni 34
4 20/11 New Activities and Intents Yonatan 34
5 27/11 Lifecycles Yarkoni 34
6 4/12 Databases and stuff Britt 34

35. Be CRUD!
Basic operations of persisting data
Read more: https://en.wikipedia.org/wiki/Create,_read,_update_and_delete

36. Be CRUD!
What’s important for us to know after each operation?
Create - ID of the new record
Read - the record-set
Update - # changed records
Delete - # deleted records

37. Creating our table
CREATE TABLE Sessions (
_id INTEGER PRIMARY KEY,
date TEXT,
title TEXT,
lecturer TEXT,
floor INTEGER
)
Read More: https://www.sqlite.org/lang_createtable.html

38. Delete a table.
DROP TABLE IF EXISTS (table)

39. Things I didn’t talk about
Using multiple tables, defining relations
Designing databases (3NF, 5NF, Inheritance modeling)
Using indexing to improve performance
Thread-safety, reader/writers, locking, ...
Triggers, Views
Transactions

40. Major Challenges (For us)
Avoid SQL Injection
Upgrade when needed
Being up-to-date

41. SQL Injection

42. What is SQL Injection?
Users:
Username Password
guest 1234
admin VeryHardPassword
Britt Dre@mB!g
Yonatan I3>starWars
Yossi @ndr0id
Yarkoni BBB4Ever!

43. How to log in?

44. Try : Strings concatenation
“SELECT * “ +
“FROM users “ +
“WHERE (username=’” + username +
”’) and (password=’” + password + “‘)“

45. Try 1: Strings concatenation
For username = “guest” and password = “1234”:
“SELECT * “ +
“FROM users “ +
“WHERE (username=’” + username +
”’) and (password=’” + password + “‘)“

46. Try 1: Strings concatenation
For username = “guest” and password = “1234”:
SELECT *
FROM users
WHERE (username=’guest’)
and (password=’1234‘)

47. Try 2: Strings concatenation
For username = “admin” and password = “a or (1=1)) --”:
“SELECT * “ +
“FROM users “ +
“WHERE (username=’” + username +
”’) and (password=’” + password + “‘)“

48. Try 2: Strings concatenation
For username = “admin” and password = “a or (1=1)) --”:
SELECT *
FROM users
WHERE (username=’admin’)
and (password=’a or (1=1)) -- ‘)
Read more: https://en.wikipedia.org/wiki/SQL_injection

49. Solution: Use Query Parameters
Use this string:
“SELECT * “ +
“FROM users “ +
“WHERE (username=?) and (password=?)“
and pass the input as Query Parameters.

50. Solution: Use Query Parameters
For username = “admin” and password = “a or (1=1)) --”:
“SELECT * “ +
“FROM users “ +
“WHERE
(username=“admin”) and (password=“a or (1=1)) --”)“

51. Try 2: Strings concatenation
For username = “admin” and password = “a or (1=1)) --”:
SELECT *
FROM users
WHERE (username=’admin’)
and (password=’a or (1=1)) -- ‘)
Read more: https://en.wikipedia.org/wiki/SQL_injection

52. Questions?

53. Upgrade

54. Application
Content Provider
DataBase (SQLite)
SQLiteOpenHelper

55. What’s hard about Upgrades?
- keep track of schema’s version.
- perform upgrade steps for each schema version.
- detect when to do it
- You need to think about how to upgrade the schema,
what to do with existing data, setting default values, etc.

56. OpenDB if it exists
Create DB if doesn’t
Upgradeif necessary.
SQLiteOpenHelper for the rescue!
Reference: http://developer.android.com/reference/android/database/sqlite/SQLiteOpenHelper.html

57. Subclass by implementing:
- onCreate(SQLiteDatabase)
- onUpgrade(SQLiteDatabase, int, int).
SQLiteOpenHelper for the rescue!
Reference: http://developer.android.com/reference/android/database/sqlite/SQLiteOpenHelper.html

58. Easier for ContentProviders
to defer opening and upgrading the database until first use,
to avoid blocking application startup with long-running database
upgrades.
SQLiteOpenHelper for the rescue!
Reference: http://developer.android.com/reference/android/database/sqlite/SQLiteOpenHelper.html

59. You have 2 methods that you use to get a SQLiteDatabase:
getReadableDatabase() and getWritableDatabase()
SQLiteOpenHelper for the rescue!

60. Cursor query(String table,
String[] columns,
String selection,
String[] selectionArgs,
String groupBy,
String having,
String orderBy)
long insert(String table,
String nullColumnHack,
ContentValues values)
What To Do With SQLiteDatabase ?
int update(String table,
ContentValues values,
String whereClause,
String[] whereArgs)
int delete(String table,

61. Don’t hard-code Strings

62. Don’t hard-code Strings
- Most Strings will be reused.
- Access same resource from different objects
Good practice: extract them into a single Contract class.

63. Don’t hard-code Strings
The contract class contains:
- Table and column names
- URI Related stuff, such as
- Content Authorities
- Build methods
- Parse methods

64. Developer Responsibilities

65. Developer Responsibilities
1.extend SQLiteOpenHelper
2.Implement onCreate and onUpdate
3.Create a constructor,
Call the super’s constructor with:
a. A Context
b. Database name
c. An optional Cursor Factory (which we won’t use, so we’ll pass null)

66. 1.Extend SQLiteOpenHelper
public class AndroidAcademyDatabaseHelper
extends SQLiteOpenHelper {
}

67. 2.onCreate and onUpgrade
public class AndroidAcademyDatabaseHelper extends SQLiteOpenHelper {
@Override
public void onCreate(SQLiteDatabase db) {
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion,
int newVersion) {
}
}

68. 2.onCreate and onUpgrade
public class AndroidAcademyDatabaseHelper extends SQLiteOpenHelper {
String sqlCreation =
"CREATE TABLE Sessions ( " +
"_id INTEGER PRIMARY KEY, " +
"date TEXT, " +
"title TEXT, " +
"lecturer TEXT, " +
"floor INTEGER " +
")";
@Override
public void onCreate(SQLiteDatabase db) {
db.execSQL(sqlCreation);
createInitialData(db);
}
}

69. 2.onCreate and onUpdate
public class AndroidAcademyDatabaseHelper extends SQLiteOpenHelper {
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion,
int newVersion) {
db.execSQL("DROP TABLE IF EXISTS Sessions");
onCreate(db);
}
}

70. 3.Constructor
public class AndroidAcademyDatabaseHelper extends SQLiteOpenHelper {
public AndroidAcademyDatabaseHelper(Context context){
super(context, "androidacademy.db", null, 1);
}
}

71. 4.Optional: Extract Contract
public class AndroidAcademyContract {
public static class SessionEntry implements BaseColumns {
public static final String TABLE_NAME = "Sessions";
public static final String COLUMN_DATE = "date";
public static final String COLUMN_TITLE = "title";
public static final String COLUMN_LECTURER = "lecturer";
public static final String COLUMN_FLOOR = "floor";
}
}

72. 4.Optional: Extract Contract
then, use Contract in the helper. For example:
private static final int DATABASE_VERSION = 1;
private static final String DATABASE_NAME = "androidacademy.db";
private static final String SQL_CREATION = "CREATE TABLE " +
AndroidAcademyContract.SessionEntry.TABLE_NAME + " ( " +
AndroidAcademyContract.SessionEntry._ID + " INTEGER PRIMARY KEY, " +
AndroidAcademyContract.SessionEntry.COLUMN_DATE + " TEXT, " +
AndroidAcademyContract.SessionEntry.COLUMN_TITLE + " TEXT, " +
AndroidAcademyContract.SessionEntry.COLUMN_LECTURER + " TEXT, " +
AndroidAcademyContract.SessionEntry.COLUMN_FLOOR + " INTEGER " +
")";

73. Demo Time
1.in onCreate we set the ListView with a cursor adapter,
but with no cursor.
We also create the DB helper there.
2.when we refresh, or do something,
that’s when we hit the DB for the first time -
and if it doesn’t exist, we create it.
3.There’s no Observing mechanism when using the dbHelper
directly.

74. 5.(Bonus!) implement CRUD on the Helper
Making the SQL Helper a full blown Data-Access-Object (or DAO).
public void insertSession(SQLiteDatabase db,
String date, String title, String lecturer, Integer floor) {
ContentValues values = new ContentValues();
values.put(AndroidAcademyContract.SessionEntry.COLUMN_DATE, date);
values.put(AndroidAcademyContract.SessionEntry.COLUMN_TITLE, title);
values.put(AndroidAcademyContract.SessionEntry.COLUMN_LECTURER, lecturer);
values.put(AndroidAcademyContract.SessionEntry.COLUMN_FLOOR, floor);
db.insert(AndroidAcademyContract.SessionEntry.TABLE_NAME, null, values);
}
Read more: https://en.wikipedia.org/wiki/Data_access_object

75. Application
Content Provider
DataBase (SQLite)
SQLiteOpenHelper Contract

76. Any questions?

77. The Relationship Between Apps And Data

78. Application
Content Provider
DataBase (SQLite)
SQLiteOpenHelper
Insert
Query
Update
Delete
Contract

79. the standard interface that connects
data in one process
with code running in another process.
Content Provider
API Guide: http://developer.android.com/guide/topics/providers/content-providers.html
Application
Content Provider
Database
Insert
Query
Update
Delete
Data Layer:

80. - encapsulate the data
- manage access to db
- mechanisms for data security.
Content Provider - Role
API Guide: http://developer.android.com/guide/topics/providers/content-providers.html
Application
Content Provider
Database
Insert
Query
Update
Delete
Data Layer:

81. When to use it?
- Share data between apps:
- offer complex data or files to other applications
- allow users to copy complex data from your app into other apps
- use android dbs: contacts, calendar, sms...
- Android Framework:
- widgets, search, sync adapter, cursor loader
- Abstraction

82. 1.extend ContentProvider
2.Register in Manifest
3.Use your content provider with a Content Resolver
Content Provider Recipe

83. 1.extend ContentProvider
implement these methods:
- query
- delete
- update
- insert
- getTypehttp://developer.android.com/guide/topics/providers/content-provider-creating.html#RequiredAccess

84. 1.extend ContentProvider
Each implementation should be about 3 things:
1.What’s the URI? What does the user want to do?
2.Use the datasource (if applicable)
3.Notify the change to everyone (if applicable)
http://developer.android.com/guide/topics/providers/content-provider-creating.html#RequiredAccess

85. query()
public Cursor query(Uri uri,
String[] projection,
String selection,
String[] selectionArgs,
String sortOrder)
This is super-easy to implement with the SQLiteOpenHelper.
Also: cursor.setNotificationUri(getContext().getContentResolver(), uri);

86. public Uri insert(Uri uri, ContentValues values);
To create this URI, you can use the URI.BuildUpon.
Also: getContext().getContentResolver().notifyChange(uri, null);
insert()

87. update()
public int update(Uri uri,
ContentValues values,
String selection,
String[] selectionArgs)
Also: getContext().getContentResolver().notifyChange(uri, null);

88. delete()
public int delete(Uri uri, String selection,
String[] selectionArgs)
Also: getContext().getContentResolver().notifyChange(uri, null);

89. Returns a string, that identifies your data structure.
Format:
getType()
Read more: http://developer.android.com/guide/topics/providers/content-provider-creating.html#TableMIMETypes
item
dir
/vnd.<name>.<type>
For single Items
For sets
Usually, Your app
namespace
Depends on
the URI
vnd.android.cursor
.

90. onCreate
Returns true if the creation was a success.
it should be quick, (it usually runs on the UI thread)
so it’s not the right place to do a database update.
Lucky for us, SQLiteOpenHelper is ...
Read More: http://developer.android.com/guide/topics/providers/content-provider-creating.html#OnCreate

91. 1.extend ContentProvider
2.Register in Manifest
3.Use your content provider with a Content Resolver
Content Provider Recipe

92. 2.Register in Manifest
In order for Android to find your Content Provider (given a URI),
You must register it in the App’s Manifest, as such:
<provider
android:authorities="com.example.androidacademy.session5.nosql.provider"
android:name=".NoSQLContentProvider" />
<provider
android:authorities="com.example.androidacademy.session5.sql.provider"
android:name=".SQLContentProvider" />

93. 1.extend ContentProvider
2.Register in Manifest
3.Use your content provider with a Content Resolver
Content Provider Recipe

94. 3.Using it (Part 1)
NEVER use a ContentProvider directly!
Ask a ContentResolver to do the work for you,
which has all CRUD methods you’ll need.

95. Application
ContentResolver
Content Provider
DataBase (SQLite)
SQLiteOpenHelper
Insert
Query
Update
Delete
Contract

96. 3.Using it (Part 1)
public void refresh(View view) {
Cursor cursor = getContentResolver()
.query(SQLProviderContract.NumberEntries.CONTENT_URI,
null,
null,
null,
null);
adapter.swapCursor(cursor);
}

97. 3.Using it (Part 1)
public void insertARandomNumber(View view) {
Random random = new Random();
int randomNumber = random.nextInt(100);
ContentValues newNumberValues = new ContentValues();
newNumberValues.put(SQLProviderContract.NumberEntries.COLUMN_NUMBER,
randomNumber);
getContentResolver()
.insert(SQLProviderContract.NumberEntries.CONTENT_URI,
newNumberValues);
}

98. 3.Using it (Part 2) - Next Session
Next time
We’ll see how to properly use a content provider to:
keep your activities synced with the data
perform loading on a background thread
keep it safe with the Activity Lifecycle.

99. Any questions?

100. Demo Time
2 Content Providers: Both keep track of numbers.
The first uses an ArrayList<Integer> as a backing store,
The other uses a SQL database.
Interesting: Cursor Observation on the content provider.

101. So why UDACITY’s code
is so complicated?

102. 3 things to spice-up your Provider
URI Matching
Handling URIs
SQLiteQueryBuilder

103. URI Matching
Supporting a few kinds of URIs
content://com.example.android.sunshine.app/location
content://com.example.android.sunshine.app/weather/
content://com.example.android.sunshine.app/weather/London
content://com.example.android.sunshine.app/weather/London/15-DEC-2015
Each is treated differently

104. URI Matching
Each URI identifies with an ID
To choose the treatment

105. URI Matcher
URI URI IDURIMatcher

106. But There Can Be Countless URIs!
content://com.example.android.sunshine.app/weather/
content://com.example.android.sunshine.app/weather/London
content://com.example.android.sunshine.app/weather/TelAviv
content://com.example.android.sunshine.app/weather/Berlin
content://com.example.android.sunshine.app/weather/Milan

107. URI Matcher - Set Up
matcher.addURI(authority, URI_TEMPLATE, ID);
URI Template ID
WeatherContract.PATH_WEATHER WEATHER
WeatherContract.PATH_WEATHER + "/*" WEATHER_WITH_LOCATION
WeatherContract.PATH_WEATHER + "/*/#" WEATHER_WITH_LOCATION_AND_DATE

108. URI Matcher - Useage
final int match = sUriMatcher.match(uri);
URI URI IDURIMatcher

109. URI Matching
What does it mean for each Content Provider method?
- query
- delete
- update
- insert
- getType

110. Application
ContentResolver
Content Provider
DataBase (SQLite)
SQLiteOpenHelper
Contract
URIMatcher
Insert
Query
Update
Delete

111. Pro Tip: Get Parameters from URI
uri.getPathSegments().get(1)
→ content://authority/words/party
uri.getQueryParameter(“q”)
→ content://google.com/search?q=Party

112. Any questions?

113. Thank you!!