Introduction to RethinkDB : DevMountain

Workshop given at Dev Mountain on May 6th, 2015.

Transcript

1. RethinkDB The database for the realtime web DevMountain Provo, Utah May 6, 2015
2. Jorge Silva @thejsj Developer Evangelist @ RethinkDB
3. Introduction What is RethinkDB?
4. 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
5. 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
6. RethinkDB Structure Database → Table → Document MySQL: Database → Table → Row MongoDB: Database → Collection → Document
7. Sample Document { "name": "Will Riker", "position": "Commander", "height": 193, "birthdate": Mon Aug 19 2335, "ships": [ { "name": "USS Pegasus" }, { "name": "USS Potemkin" }, { "name": "USS Enterprise" }, ], ... }
8. Installing RethinkDB http://rethinkdb.com/install/
9. http://rethinkdb-chat.thejsj.com:10001/ #dataexplorer http://bit.ly/1zMCJH2 Having Issues?
10. Introduction to ReQL RethinkDB Query Language
11. Introduction to ReQL • ReQL embeds natively into your programming language • Compose ReQL queries by chaining commands
12. Anatomy of a ReQL Query r.table("users") .pluck("last_name") .distinct().count() Number of unique last names
13. Anatomy of a ReQL Query r.table("users") .pluck("last_name") .distinct().count() Access a database table
14. Anatomy of a ReQL Query r.table("users") .pluck("last_name") .distinct().count() Isolate a document property
15. Anatomy of a ReQL Query r.table("users") .pluck("last_name") .distinct().count() Consolidate duplicate values
16. Anatomy of a ReQL Query r.table("users") .pluck("last_name") .distinct().count() Display the number of items
17. 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"})
18. 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
19. Running Queries http://bit.ly/1JQ8imw
20. Secondary Indexes • Queries performed against indexes are much faster • Can index on a single property, multiple fields, or arbitrary ReQL expressions
21. Querying an Index r.table("fellowship") .indexCreate("species") r.table("fellowship") .getAll("human", {index: "species"}) Find all humans in “fellowship”
22. Running Queries: Indexes
23. 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:
24. 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))
25. Running Queries: Functions
26. 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
27. Running Queries: Query Composition
28. 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
29. Additional ReQL Features • Geospatial indexing for location- based queries • Date and time functions for time data • Support for storing binary objects
30. Realtime Updates Working with Changefeeds
31. Subscribe to change notifications on database queries Changefeeds
32. r.table("users").changes() Track changes on the users table Changefeeds
33. Changefeeds • The changes command returns a cursor that receives updates • Each update includes the new and old value of the modified record
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 }
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', ... } }
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' } }
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:
38. 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:
39. Using Changefeeds
40. Building Web Apps Using RethinkDB in Node
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
42. > Client Driver Install the JS client driver from NPM in your Node.js project: $ npm install rethinkdb --save
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() { // Documented inserted }); Add Bob to the “users” table
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
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
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
47. 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
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
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
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
51. 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
52. 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
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
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
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
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
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
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
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
60. Socket.io (Client) <html> <head> <title>Real-time web app</title> <script src="/socket.io/socket.io.js"></script> <script> var socket = io.connect(); socket.on("update", function(data) { console.log("Update:", data); }); Receive Socket.io updates on frontend
61. Socket.io (Client) <html> <head> <title>Real-time web app</title> <script src="/socket.io/socket.io.js"></script> <script> var socket = io.connect(); socket.on("update", function(data) { console.log("Update:", data); }); Load the Socket.io client script
62. Socket.io (Client) <html> <head> <title>Real-time web app</title> <script src="/socket.io/socket.io.js"></script> <script> var socket = io.connect(); socket.on("update", function(data) { console.log("Update:", data); }); Connect to the Socket.io server
63. Socket.io (Client) <html> <head> <title>Real-time web app</title> <script src="/socket.io/socket.io.js"></script> <script> var socket = io.connect(); socket.on("update", function(data) { console.log("Update:", data); }); Create handler for “update” messages
64. Socket.io (Client) <html> <head> <title>Real-time web app</title> <script src="/socket.io/socket.io.js"></script> <script> var socket = io.connect(); socket.on("update", function(data) { console.log("Update:", data); }); Display update in browser console
65. Tutorial: Building a chat app
66. #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
67. #2: Create database and tables (P
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68. #3: Insert sample data (P
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69. #4: Go to server/index.js -PPL
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72. #5: Switch database $POOFDU
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73. Additional Resources • RethinkDB website:
 http://rethinkdb.com • RethinkDB cookbook:
 http://rethinkdb.com/docs/cookbook • RethinkDB installation:
 http://rethinkdb.com/docs/install/