Why you may want to use PouchDB for handling your data storage and synchronization needs in your mobile apps.

1. EASY DATA FOR PHONEGAP
APPS
HOLLY SCHINSKY
PHONEGAP TEAM AT ADOBE

2. SOCIAL INFO
@devgirl
devgirl.org
https://github.com/hollyschinsky

3. COUCHDB
1st NoSQL document database created in 2005
Prefer "availability" and near real-time "consistency"
Stores unstructured "documents" using JSON
Runs on the server with RESTful API's
Designed for synchronization/replication

4. COUCHDB CONT...
CAP theorem ~ Partitioned, every node is
Available, and it's only eventually
Consistent.

5. POUCHDB?
JavaScript implementation of CouchDB for the
browser/nodejs
Mimics CouchDB API for consistency between client
and remote servers
JS abstraction layer over WebSQL, IndexedDB and
LevelDB etc
Build o ine apps that sync when back online

6. SAMPLE "DOCUMENT"
{
"_id": "mittens",
"name": "Mittens",
"occupation": "kitten",
"age": 3,
"hobbies": [
"playing with balls of yarn",
"chasing laser pointers",
"lookin' hella cute"
]
}

7. DATA SYNCHRONIZATION
Credit: http://www.ibm.com/developerworks/library/wa-couchdb/
Multiple options to replicate data between source and
target.

8. UNIDIRECTIONAL REPLICATION
Sync data from source to target or target to source...
localDB.replicate.to(remoteDB);
OR...
localDB.replicate.from(remoteDB);

9. BIDIRECTIONAL REPLICATION
Sync data from src to target AND target to src:
localDB.replicate.to(remoteDB);
localDB.replicate.from(remoteDB);
is the same as using...
localDB.sync(remoteDB, [options]);

10. LIVE REPLICATION
Changes propagated as they occur with liveparameter
myApp.db.sync(myApp.remoteDB, {
live: true
retry: true
}).on('change', function (change) {
console.log("A db change occurred " + change);
}).on('paused', function (info) {
console.log("Replication paused " + info);
}).on('active', function (info) {
console.log("Replication resumed " + info);
}).on('error', function (err) {
console.log("Sync Error occurred " + err);
})

11. FILTERED REPLICATION
Replicate partial datasets
Use case - return certain documents based on a users
identity or role
localDb.replicate.from(remoteDB, {
filter: function (doc) {
return doc.category === role;
}
}

12. DESIGN FOR OFFLINE FIRST
Better user experience (o ine and online)
Allow users to continue to work o ine
Avoid discontinued use of your apps

13. WHEN OFFLINE?
Rural Areas
3rd World Countries
Limited, Sporadic or No Access (airplanes)

14. OFFLINE APP USE CASES
Inspection Apps
Content Publishing (books, music, videos)
Health Care
Social Media
Location/Mapping Apps
Retail
Games

15. BROWSER STORAGE OPTIONS
HTML5 Storage - local storage
IndexedDB - new standard
WebSQL - deprecated

16. DATABASE BROWSER SUPPORT
Current defaults (can use adapters to change)

17. POUCHDB ADAPTERS

18. POUCHDB + SQLITE
Avoid storage limits of other solutions
Use WKWebView (WebSQL not available and
IndexedDB slow/buggy)
Allows you to bundle prepopulated database les
(avoid db init overhead)

19. Credit: http://www.html5rocks.com/en/tutorials/o ine/quota-research/#toc-mobile
MOBILE DATA STORAGE LIMITS

20. POUCHDB CORDOVA SQLITE ADAPTER
Provides native SQLite support w/ WebSQL like API
Use in addition to one of 3 Cordova Plugins - (
, or
)
Requires pouchdb.js (6.0.0+)
pouchdb-adapter-cordova-sqlite
Cordova-
sqlite-storage cordova-plugin-sqlite-2 cordova-
plugin-websql
myApp.localDB = new PouchDB('tasks.db', {adapter: 'cordova-sqlite'});

21. POUCHDB SERVER
https://github.com/pouchdb/pouchdb-serve
A simple server to mimic a CouchDB implementation
to get started quickly
Includes Web UI admin tool
$ pouchdb-server -p 15984

22. LOCAL/REMOTE DATABASE SETUP
// Create the local database
if (ons.platform.isIOS() || ons.platform.isAndroid())
myApp.localDB = new PouchDB('tasks.db', {adapter: 'cordova-sqlite'});
else myApp.localDB = new PouchDB('tasks.db');
// Create the remote database
myApp.remoteDB = new PouchDB("http://localhost:15984/tasks");
// Start Syncing
myApp.localDB.sync(myApp.remoteDB, {live: true, retry: true});

23. SAMPLE APP
Source Project:
https://github.com/hollyschinsky/PouchDB-Sample

24. USEFUL RESOURCES
PouchDB PhoneGap/Cordova Getting Started
PouchDB Ionic Getting Started
Cloudant DBaaS
Couchbase
PouchDB Server
Set up CouchDB Server
PouchDB Inspector
PouchDB Find
PouchDB Plugins
Database Comparison Tool