Workshop: Introduction to RethinkDB : Santa Cruz JS

Transcript

1. RethinkDB
   The database for the
   realtime web
   Santa Cruz JS
   Santa Cruz, California
   July 9, 2015
   

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2. Jorge Silva
   @thejsj
   Developer Evangelist @ RethinkDB
   

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3. Schedule
   1. What is RethinkDB?
   2. RethinkDB query language
   3. Working with changefeeds
   4. Using RethinkDB with Node.js
   5. Tutorial: Building a chat app
   

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4. Introduction
   What is RethinkDB?
   

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

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7. Built for Realtime Apps
   • Having your database push
   changes keeps your database as
   the central source of truth
   • Having a central source of truth
   simplifies your architecture
   

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8. Power and Convenience
   • Highly expressive query language
   • Relational features like table joins
   • Powerful admin UI with point-
   and-click cluster management
   

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

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10. 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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11. Differences with Firebase
    • Firebase is a cloud service, not an
    open-source database
    • Because Firebase is not a database,
    it has limited querying abilities
    • Firebase is made to be queried
    from the browser
    

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12. Differences with MongoDB
    • RethinkDB supports joins and
    subqueries
    • MongoDB only supports the
    traditional query-response model.
    You can't subscribe to queries.
    

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13. Introduction to ReQL
    RethinkDB query language
    

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

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

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

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

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

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

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20. Sample ReQL Queries
    r.table("users")
    .filter(r.row("age").gt(30))
    r.table(“posts")
    .eqJoin(“userId”, r.table(“users”))
    .zip()
    r.table("posts")
    .filter({status: "draft"})
    .update({status: "published"})
    

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21. 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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22. 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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23. 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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24. 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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25. 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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26. Understanding ReQL
    • All queries are executed by the
    database, not the client
    • 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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27. Additional ReQL Features
    • Geospatial indexing for location-
    based queries
    • Date and time functions
    • Support for storing binary objects
    • Execute http requests using r.http
    

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28. Running Queries
    https://github.com/thejsj/rethinkdb-workshop
    

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29. http://rethinkdb.thejsj.com:8080
    Running Queries
    

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30. Realtime Updates
    Working with Changefeeds
    

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31. Subscribe to change notifications
    on database queries
    Changefeeds
    

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

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33. 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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34. 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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35. 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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36. 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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37. 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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38. Changefeeds
    r.table("table").get(ID).changes()
    r.table("table").getAll(ID).changes()
    r.table("table").between(X, Y).changes()
    r.table("table").pluck(X, Y, Z).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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39. Using Changefeeds
    

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40. Building Web Apps
    Using RethinkDB in Node
    

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41. 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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42. >
    Client Driver
    Install the JS client driver from
    npm in your Node.js project:
    $ npm install rethinkdb --save
    

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43. 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() {
    // Document inserted
    });
    Add Bob to the “users” table
    

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44. 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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45. 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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46. 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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47. 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);
    });
    Run the query on a connection
    

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48. 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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49. 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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50. 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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51. Using Changefeeds
    Attach a changefeed to the table
    r.connect().then(function(conn) {
    return r.table("fellowship")
    .changes().run(conn);
    })
    .then(function(cursor) {
    cursor.each(function(err, item) {
    console.log(item);
    });
    });
    

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

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53. 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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54. 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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55. 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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56. 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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57. 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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58. 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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59. 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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60. Socket.io (Client)
    
    
    Real-time web app
    
    <br/>var socket = io.connect();<br/>socket.on("update", function(data) {<br/>console.log("Update:", data);<br/>});<br/>Receive Socket.io updates on frontend<br/>

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

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

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

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

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65. Tutorial: Building a chat app
    

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66. #1: Clone the repository
    Clone From GitHub:
    git clone https://github.com/thejsj/
    rethinkdb-workshop.git
    Download Tarball:
    https://github.com/thejsj/rethinkdb-
    workshop/tarball/master
    

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67. #2: Install Dependencies
    // Go to the project directory
    cd rethinkdb-workshop
    // Install dependencies
    npm install
    

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68. #3: Go to config/default.js
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    var config = {
    "rethinkdb": {
    "host": "localhost", // or rethinkdb.thejsj.com
    "port": 29015,
    "db" : "rethinkdb_workshop"
    // or GITHUB_HANDLE_rethinkdb_workshop
    },
    

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69. #4: Run Server
    // Start server
    npm run dev // or `node server`
    

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70. #4: Go to server/index.js
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    // Step 1
    // Write a query
    

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71. Connections
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    r.table("messages").run(r.conn);
    

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72. #5: Switch database
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    var config = {
    "rethinkdb": {
    "host": "rethinkdb.thejsj.com",
    "port": 29015,
    "db" : "GITHUB_HANDLE_rethinkdb_workshop"
    },
    

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73. Next steps
    • Advanced Commands: `r.do`,
    `r.branch`, `r.forEach`
    • Map/Reduce queries
    • Indexes (multi, compound, index
    functions, geospatial)
    • Sharding and replication
    

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74. Questions
    • RethinkDB website:

    http://rethinkdb.com
    • Install RethinkDB:

    http://rethinkdb.com/install/
    • Email me: jorge@rethinkdb.com
    • Tweet: @thejsj, @rethinkdb
    

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