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RethinkDB The database for the realtime web DevMountain Provo, Utah May 6, 2015

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Jorge Silva @thejsj Developer Evangelist @ RethinkDB

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Introduction What is RethinkDB?

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What is RethinkDB? • Open source database for building realtime web applications • NoSQL database that stores schemaless JSON documents • Distributed database that is easy to scale

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Built for Realtime Apps • Subscribe to change notifications from database queries • No more polling — the database pushes changes to your app • Reduce the amount of plumbing needed to stream live updates

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RethinkDB Structure Database → Table → Document MySQL: Database → Table → Row MongoDB: Database → Collection → Document

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Sample Document { "name": "Will Riker", "position": "Commander", "height": 193, "birthdate": Mon Aug 19 2335, "ships": [ { "name": "USS Pegasus" }, { "name": "USS Potemkin" }, { "name": "USS Enterprise" }, ], ... }

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Installing RethinkDB http://rethinkdb.com/install/

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http://rethinkdb-chat.thejsj.com:10001/ #dataexplorer http://bit.ly/1zMCJH2 Having Issues?

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Introduction to ReQL RethinkDB Query Language

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Introduction to ReQL • ReQL embeds natively into your programming language • Compose ReQL queries by chaining commands

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Anatomy of a ReQL Query r.table("users") .pluck("last_name") .distinct().count() Number of unique last names

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Anatomy of a ReQL Query r.table("users") .pluck("last_name") .distinct().count() Access a database table

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Anatomy of a ReQL Query r.table("users") .pluck("last_name") .distinct().count() Isolate a document property

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Anatomy of a ReQL Query r.table("users") .pluck("last_name") .distinct().count() Consolidate duplicate values

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Anatomy of a ReQL Query r.table("users") .pluck("last_name") .distinct().count() Display the number of items

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Sample ReQL Queries r.table("users") .filter(r.row("age").gt(30)) r.table("users") .pluck("last_name") .distinct().count() r.table("fellowship") .filter({species: "hobbit"}) .update({species: "halfling"})

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ReQL Commands • Transformations: map, orderBy, skip, limit, slice • Aggregations: group, reduce, count, sum, avg, min, max, distinct, contains • Documents: row, pluck, without, merge, append, difference, keys, hasFields, spliceAt • Writing: insert, update, replace, delete • Control: forEach, range, branch, do, coerceTo, expr

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Running Queries http://bit.ly/1JQ8imw

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Secondary Indexes • Queries performed against indexes are much faster • Can index on a single property, multiple fields, or arbitrary ReQL expressions

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Querying an Index r.table("fellowship") .indexCreate("species") r.table("fellowship") .getAll("human", {index: "species"}) Find all humans in “fellowship”

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Running Queries: Indexes

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Anonymous Functions r.range(5).map(function(i) { return i.mul(2); }) Multiply each value by 2 You can pass anonymous functions to commands like map and reduce:

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The r.row command Multiply each value by 2 You can often use r.row instead of an anonymous function: r.range(5).map(r.row.mul(2))

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Running Queries: Functions

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Query Composition • ReQL embeds natively in your programming language • Pass around ReQL expressions like any other code • You can assign ReQL expressions to variables or store them in functions

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Running Queries: Query Composition

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Understanding ReQL • Anonymous function must return a valid ReQL expression • Client driver translates ReQL queries into wire protocol • In JS use e.g. the mul and gt commands instead of the normal operators

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Additional ReQL Features • Geospatial indexing for location- based queries • Date and time functions for time data • Support for storing binary objects

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Realtime Updates Working with Changefeeds

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Subscribe to change notifications on database queries Changefeeds

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r.table("users").changes() Track changes on the users table Changefeeds

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Changefeeds • The changes command returns a cursor that receives updates • Each update includes the new and old value of the modified record

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Changefeeds r.table("users").changes() r.table("users") .insert({name: "Bob"}) Changefeed output: { new_val: { id: '362ae837-2e29-4695-adef-4fa415138f90', name: 'Bob', ... }, old_val: null }

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Changefeeds r.table("users").changes() r.table("users") .filter({name: "Bob"}).delete() Changefeed output: { new_val: null, old_val: { id: '362ae837-2e29-4695-adef-4fa415138f90', name: 'Bob', ... } }

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Changefeeds r.table("users").changes() r.table("users") .get("362ae837-2e29-4695-adef-4fa415138f90") .update({name: "Bobbby"}) Changefeed output: { new_val: { id: '362ae837-2e29-4695-adef-4fa415138f90', name: 'Bobby' }, old_val: { id: '362ae837-2e29-4695-adef-4fa415138f90', name: 'Bob' } }

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Changefeeds r.table("players") .orderBy({index: r.desc("score")}) .limit(3).changes() Track top three players by score Chain the changes command to an actual ReQL query:

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Changefeeds r.table("table").get(ID).changes() r.table("table").getAll(ID).changes() r.table("table").between(X, Y).changes() r.table("table").filter(CONDITION).changes() r.table("table").union(ID).changes() r.table("table").map(FUNCTION).changes() r.table("table").min(INDEX).changes() r.table("table").max(INDEX).changes() r.table("table").orderBy(INDEX) .limit(N).changes() Commands that currently work with changefeeds:

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Using Changefeeds

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Building Web Apps Using RethinkDB in Node

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Client Driver • Use a RethinkDB client driver to access the database in your app • Official drivers available for Ruby, Python, and JavaScript • Third-party drivers available for other languages like Go and Clojure

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> Client Driver Install the JS client driver from NPM in your Node.js project: $ npm install rethinkdb --save

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Client Driver var r = require("rethinkdb"); r.connect().then(function(conn) { return r.table("users") .insert({name: “Bob”}).run(conn) .finally(function () { conn.close(); }); }).then(function() { // Documented inserted }); Add Bob to the “users” table

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Client Driver var r = require("rethinkdb"); r.connect().then(function(conn) { return r.table("users") .insert({name: “Bob"}).run(conn) .finally(function () { conn.close(); }); }).then(function(output) { console.log(output); }); Import the RethinkDB module

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Client Driver var r = require("rethinkdb"); r.connect().then(function(conn) { return r.table("users") .insert({name: “Bob”}).run(conn) .finally(function () { conn.close(); });; }).then(function(output) { console.log(output); }); Connect to the database

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Client Driver var r = require("rethinkdb"); r.connect().then(function(conn) { return r.table("users") .insert({name: “Bob”}).run(conn) .finally(function () { conn.close(); }); }).then(function(output) { console.log(output); }); ReQL query that inserts a record

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Client Driver var r = require("rethinkdb"); r.connect().then(function(conn) { return r.table("users") .insert({name: “Bob”}) .run(conn, function (err, output) { console.log(output); }) }) Run the query on a connection

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Client Driver var r = require("rethinkdb"); r.connect().then(function(conn) { return r.table("users") .insert({name: “Bob"}).run(conn) .finally(function () { conn.close(); }); }).then(function(output) { console.log(output); }); Display query response

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Client Driver var r = require("rethinkdb"); r.connect().then(function(conn) { return r.table("users") .insert({name: “Bob"}).run(conn) .finally(function () { conn.close(); }); }).then(function(output) { console.log(output); }).error(function(err) { console.log("Failed:", err); }); Handle errors emitted by Promise

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Using Changefeeds r.connect().then(function(conn) { return r.table("fellowship") .changes().run(conn); }) .then(function(cursor) { cursor.each(function(err, item) { console.log(item); }); }); Display every change on the “fellowship” table

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Using Changefeeds r.connect().then(function(conn) { return r.table("fellowship") .changes().run(conn, function (err, cursor) {
 cursor.each(function(err, item) { console.log(item); }); }); Attach a changefeed to the table

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Using Changefeeds r.connect().then(function(conn) { return r.table("fellowship") .changes().run(conn); }) .then(function(cursor) { cursor.each(function(err, item) { console.log(item); }); }); Iterate over every value passed into the cursor

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Using Changefeeds r.connect().then(function(conn) { return r.table("fellowship") .changes().run(conn); }) .then(function(cursor) { cursor.each(function(err, item) { console.log(item); }); }); Display received changes in the console

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Using Socket.io • Powerful framework for realtime client/server communication • Supports WebSockets, long polling, and other transports • Lets you send JSON messages between your app and frontend

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Socket.io (Server) var sockio = require("socket.io"); var app = require("express")(); var r = require("rethinkdb"); var io = sockio.listen(app.listen(8090)); r.connect().then(function(conn) { return r.table("players") .orderBy({index: r.desc("score")}) .limit(5).changes().run(conn); }) .then(function(cursor) { cursor.each(function(err, data) { io.sockets.emit("update", data); }); }); Broadcast score changes over Socket.io

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Socket.io (Server) var sockio = require("socket.io"); var app = require("express")(); var r = require("rethinkdb"); var io = sockio.listen(app.listen(8090)); r.connect().then(function(conn) { return r.table("players") .orderBy({index: r.desc("score")}) .limit(5).changes().run(conn); }) .then(function(cursor) { cursor.each(function(err, data) { io.sockets.emit("update", data); }); }); Load the Socket.io module

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Socket.io (Server) var sockio = require("socket.io"); var app = require("express")(); var r = require("rethinkdb"); var io = sockio.listen(app.listen(8090)); r.connect().then(function(conn) { return r.table("players") .orderBy({index: r.desc("score")}) .limit(5).changes().run(conn); }) .then(function(cursor) { cursor.each(function(err, data) { io.sockets.emit("update", data); }); }); Instantiate Socket.io server

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Socket.io (Server) var sockio = require("socket.io"); var app = require("express")(); var r = require("rethinkdb"); var io = sockio.listen(app.listen(8090)); r.connect().then(function(conn) { return r.table("players") .orderBy({index: r.desc("score")}) .limit(5).changes().run(conn); }) .then(function(cursor) { cursor.each(function(err, data) { io.sockets.emit("update", data); }); }); Attach a changefeed to the query

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Socket.io (Server) var sockio = require("socket.io"); var app = require("express")(); var r = require("rethinkdb"); var io = sockio.listen(app.listen(8090)); r.connect().then(function(conn) { return r.table("players") .orderBy({index: r.desc("score")}) .limit(5).changes().run(conn); }) .then(function(cursor) { cursor.each(function(err, data) { io.sockets.emit("update", data); }); }); Broadcast updates to all Socket.io connections

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Socket.io (Client) Real-time web app var socket = io.connect(); socket.on("update", function(data) { console.log("Update:", data); }); Receive Socket.io updates on frontend

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Socket.io (Client) Real-time web app var socket = io.connect(); socket.on("update", function(data) { console.log("Update:", data); }); Load the Socket.io client script

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Socket.io (Client) Real-time web app var socket = io.connect(); socket.on("update", function(data) { console.log("Update:", data); }); Connect to the Socket.io server

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Socket.io (Client) Real-time web app var socket = io.connect(); socket.on("update", function(data) { console.log("Update:", data); }); Create handler for “update” messages

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Socket.io (Client) Real-time web app var socket = io.connect(); socket.on("update", function(data) { console.log("Update:", data); }); Display update in browser console

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Tutorial: Building a chat app

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#1: Clone the repository git clone git@github.com:thejsj/ rethinkdb-workshp.git or https://github.com/thejsj/rethinkdb- workshop/tarball/master or http://bit.ly/1cmsO0B

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#2: Create database and tables (PUPZPVSEBUBFYQMPSFSBOESVO UIFGPMMPXJOHRVFSJFT r.dbCreate(‘chat’); r.db(‘chat’).tableCreate(‘messages’); r.db(‘chat’).tableCreate(‘users’, { primaryKey: ‘email’ });

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#3: Insert sample data (PUPZPVSEBUBFYQMPSFSBOESVOUIF GPMMPXJOHRVFSZ r.table(‘messages’) .insert(r.json( r.http(‘http://bit.ly/1zMGw7b') )) r.table(‘users’) .insert(r.json( r.http(‘http://bit.ly/1zBj4tm') ))

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#4: Go to server/index.js -PPLGPSUIFDPNNFOUTJOPSEFS UPXSJUFUIFDPSSFDU3F2-RVFSJFT // Step 1 // Write a query…

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Connections *OUIJTBQQ UIFrPCKFDUDPOUBJOT BDPOOFDUJPO r.table(‘messages’).run(r.conn);

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Suggestions "EEJOHSPPNTUPDIBUBQQ "EEJOHVTFSTJOSPPNDIBU "EENVMUJQMFOPEFTUPDMVTUFS "EENFTTBHFTFBSDI "EENFTTBHFMJLJOH 4VQQPSUEFMFUJOHNFTTBHFT 4DIFNBTEFOFEJO3&"%.&

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#5: Switch database $POOFDUUPUIFGPMMPXJOH EBUBCBTF TPXFDBOBMMTIBSF NFTTBHFT { host : ‘http://', port : 28015, db : ‘chat’ }

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Additional Resources • RethinkDB website:
 http://rethinkdb.com • RethinkDB cookbook:
 http://rethinkdb.com/docs/cookbook • RethinkDB installation:
 http://rethinkdb.com/docs/install/