Getting into REAL(M) business by dumping SQLite

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Getting into REAL (M) business by dumping SQLite

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Hello! I am Dhrumil Shah I work at Bugle Technologies Pvt. Ltd. & Co-organizer at GDG Ahmedabad. You can find me at: @dhuma1981 +DhrumilShah

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“

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Why you should dump SQLite?

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Typical Apps Requirement Lot of Data Tables W orks Offline Persist Locally

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Problems :( More Data More Tables

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Duplicate Data Normalization

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Normalization More m:n

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More m:n

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BoilerPlate mess ▷ 1000’s of lines of boilerplate mess ▷ Lot of string just to define a single table ▷ Tightly coupled schema ▷ RAW SQL Queries

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Nested Queries SELECT table1.col, table3.col FROM table1 JOIN table2 ON table1.primarykey = table2.foreignkey JOIN table3 ON table2.primarykey = table3.foreignkey

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Nested Queries String query = “select” + table1.col + ”,” + table3.col + “FROM” + table1 + “JOIN” + table2 + “ON” + table1.primarykey + “=” + table2.foreignkey + “JOIN” + table3 + “ON” + table2.primarykey + “=” + table3.foreignkey

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No content

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Let’s abstract the problem Use ORM

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▷ SugarORM ▷ ORMLite ▷ CubBoard ▷ ActiveRecord ▷ Ollie ▷ DBFLow ORM Options ▷ DBQuery ▷ GreenDao ▷ EasyLiteORM ▷ RushORM ▷ SpringkilesBlack ▷ . . . .

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▷ Easy setup ▷ Abstract SQLite boilerplate codes ▷ No direct dealing with SQL ▷ Object Mapping ORM Good Part

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▷ Slow, Most ORM uses reflections, read write performance is slow ▷ Not entirely SQL free, still need to write queries for certain task ▷ And as underlying is SQLite all the issues with database scaling. ORM Bad Part

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What is Realm? Realm is an object database designed for mobile

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“ Zero Copy Object Store

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Object Store A E B D C VS

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Object Store SELECT table1.col, table3.col FROM table1 JOIN table2 ON table1.primarykey = table2. foreignkey JOIN table3 ON table2.primarykey = table3. foreignkey

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Object Store A E B D C Realm.getA().getB().getD()

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“ Zero Copy

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// create Cursor in order to parse our sqlite results Cursor cursor = sqliteDB.rawQuery("SELECT bookTitle FROM " + tableName, null); // if Cursor contains results if (cursor != null) { // move cursor to first row if (cursor.moveToFirst()) { do { // Get version from Cursor String bookName = cursor.getString(cursor.getColumnIndex("bookTitle")); } while (cursor.moveToNext()); } } What is Zero Copy

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Zero Copy Src: Building Mobile DataBase by Christian Melchior http://www.slideshare.net/ChristianMelchior/realm- building-a-mobile-database#25

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Person person = new Person() //Standard Java Person proxyperson = realm.copyToRealm(person) //Proxy object Person proxyperson = realm.createObject(Person.class) //Proxy object //Query Results are Lazy RealmResults queryResults = realm.allObjects(Person.class) queryResult.get(0) != queryResult.get(0) //different objects queryResult.get(0).equals(queryResult.get(0)) //same data Zero Copy

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▷ Easy Setup ▷ Memory mapped files ▷ C++ core ▷ B+ trees ▷ Column Oriented ▷ Minimize IO overhead ▷ Cross platform ▷ Faster Read & writes ▷ Read > Writes ▷ Simple Querying interface Designed for Mobile

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Benchmarking Benchmarking realm against other databases

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Src: Building Mobile DataBase by Christian Melchior http://www.slideshare.net/ChristianMelchior/realm- building-a-mobile-database#25

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Sample against 1,00,000 objects read and write

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Let’s See some Code

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Setup compile 'io.realm:realm-android: 0.86.1' Realm realm = Realm.getInstance(context)

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Method and Size ▷ ~ 1750 method counts ▷ adds ~730 KB fat to apk ▷ install size less

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Realm Objects //Standard Java POJO from RealmObject public class Person extends RealmObject { @PrimaryKey private String personName; private int personAge; ….. …... //Getters and Setters }

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Writing Data //Standard Java extend person from RealmObject Person person = new Person() //call setter to set data …. //save data try{ realm.beginTransaction(); realm.copyToRealm(person); realm.commitTransaction(); }catch(Exception e){ realm.cancelTransaction(); // rollback data }

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Writing Data Async Block //transaction block realm.executeTransaction(new Realm.Transaction() { @Override public void execute(Realm realm) { Person person = realm.createObject(Person.class); person.setName("John"); person.setEmail("[email protected]"); } });

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▷ Supports Primary Key ▷ Supports primitive data types like int, long, boolean etc. ▷ Supports Box types like Integer, Long, String etc. ▷ Allows null value for non primitives types ▷ Supports Indexing Realm Object

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Query Data // Build the query looking at all users: RealmQuery query = realm.where(User.class); // Add query conditions: query.equalTo("name", "John"); query.or().equalTo("name", "Peter"); // Execute the query: RealmResults result1 = query.findAll(); // Or alternatively do the same all at once (the "Fluent interface"): RealmResults result2 = realm.where(User.class) .equalTo("name", "John") .or() .equalTo("name", "Peter") .findAll();

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Query Data // Queries use Builder pattern to build up the query conditions RealmResults query = realm.where(Dog.class) .greaterThan("age", 8) .findAll(); // Queries are chainable RealmResults allRex = query.where() .contains("name", "rex") .findAll();

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▷ Conditions like lessThan, greaterThan, contains, beginsWith etc ▷ Modifiers for ignoring Cases ▷ Logical Operations OR AND ▷ Sorting Ascending, Descending ▷ Chaining Queries ▷ Aggregations like SUM, MIN, MAX, AVG ▷ Synchronous, Asynchronous operations Query Data Supports

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Relationships // Any Realm Object can be linked together public class Email extends RealmObject { private String address; private boolean active; // ... setters and getters left out } public class Contact extends RealmObject { private String name; private Email email; // ... setters and getters left out }

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Link Queries // You can now link queries together RealmResults contacts = realm.where(Contact. class).equalTo("emails.active", true).findAll();

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▷ Direct support for Json to Object store ▷ Notification for database change like CP ▷ Encryption support in built ▷ Adapters for binding data with views ▷ Cross Platform, same data can work across iOS and Android ▷ Robust 3rd parties addons Other Features

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Limitations

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▷ Not Entirely NOSQL, need migration on schema Changes ▷ No support for auto incrementing primary keys ▷ Closed source code ▷ Mutable, thread-confined objects ▷ No support for realm objects across threads ▷ Slower write ▷ Increase method count and size of apk Limitations

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Realm Browser

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Mac App to browse data stored on realm files (there is a separate plugin for STETHO)

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Who else is using Realm Is it production ready?

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No content

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Thanks! Any questions? You can find me at: @dhuma1981 +DhrumilShah [email protected]

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Credits Special thanks to all the people who made and released these awesome resources for free: ▷ Realm by realm.io ▷ Christian Melchior from Realm Team ▷ Pranay Airan from GDG BlrDroid ▷ Presentation template by SlidesCarnival