An Evening with MongoDB Toronto 2012 - Building Applications with MongoDB

Building Your First MongoDB Application
Randall Hunt
This talk will introduce the features of MongoDB by walking through how one can building a simple location-based checkin application using MongoDB. The talk will cover the basics of MongoDB's document model, query language, map-reduce framework and deployment architecture.
Speaker Bio: Randall is a HackNY mentor. He loves python, programming, space, and exploring NYC.

Transcript

1. An Introduction
   With Randall Hunt
   Building Applications
   With MongoDB
   @jrhunt
   

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2. Agenda
   MongoDB: Data modeling, queries,
   geospatial, updates, map reduce
   Using a location-based app as an example
   Example Works in MongoDB JS shell
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3. Why MongoDB
   Open source
   Designed for today
   Today’s hardware / environments
   Today’s challenges
   Great developer experience
   Reliable
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   •
   

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4. Use Cases
   Web, Media, SaaS, Gaming, Finance, Telecom, Healthcare, LHC
   RDBMS replacement for high-traffic web
   applications
   Content Management-type applications
   Real-time analytics
   High-speed data logging
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5. In Good Company
   

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6. Let’s Design An App
   Users Check-in to a Location
   Leave Notes and Comments About That
   Location
   Requirements, then Documents
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7. Terminology
   RDBMS MongoDB
   Table, View ➜ Collection
   Row ➜ JSON Document
   Index ➜ Index
   Join ➜ Embedded Document
   Partition ➜ Shard
   Partition Key ➜ Shard Key
   

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8. Documents
   Note: _id is unique, but can be anything
   you’d like
   {
   _id : ObjectId("4c4ba5c0672c685e5e8aabf3"),
   author : "ranman",
   date : "Sat Jul 24 2010 19:47:11",
   text : "MongoSF",
   tags : [ "San Francisco", "MongoDB" ]
   }
   

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9. Collections
   Places Users Check-Ins
   Doc 4
   Doc 5
   Doc 6
   Doc 7
   Doc 8
   Doc 9
   Doc 1
   Doc 2
   Doc 3
   

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10. Application Goals
    Places Check ins
    (1)
    Q: Current location
    A: Places near location
    (2) Add user
    generated
    content
    (3) Record user
    checkins
    (4) Stats about
    checkins
    

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11. Creating A Document
    place1 = {
    name : "10gen HQ",
    address : "578 Broadway 7th Floor",
    city : "New York",
    zip : "10012"
    }
    

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12. Inserting Places
    Initial Data Load
    > db.places.insert(place1)
    

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13. Query A Collection
    > db.places.find({zip: "10012"}).limit(10)
    {
    _id : ObjectId("01aed46179d968fc55c7232")
    name : "10gen HQ",
    address : "578 Broadway 7th Floor",
    city : "New York",
    zip : "10012"
    }
    

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14. Places v2
    place1 = {
    name : "10gen HQ",
    address : "578 Broadway 7th Floor",
    city : "New York",
    zip : "10012",
    tags : [ "business", "awesome" ]
    }
    

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15. Update A Collection
    > db.places.update({zip: "10012"},
    { tags : [ "business", "awesome" ] });
    > db.places.find({_id: ObjectId(...)})
    {
    _id : ObjectId(...)
    tags : [ "business", "awesome" ]
    }
    

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16. Updating A Collection
    > db.places.update({zip: "10012"},
    { $set :
    {
    tags : [ "business", "awesome" ]
    }
    }
    )
    

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17. Places v2
    place1 = {
    name : "10gen HQ",
    address : "578 Broadway 7th Floor",
    city : "New York",
    zip : "10012",
    tags : [ "business", "awesome" ]
    }
    > db.posts.findOne({ zip: "10012",
    tags: "awesome" })
    

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18. $push
    > db.posts.update(
    { _id: ObjectId(...)},
    { $push: {tags: "moreawesome"}}
    )
    

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19. .explain()
    > db.places.find({zip: "10012"}).explain()
    {
    "cursor" : "BasicCursor",
    "nscanned" : 2,
    "nscannedObjects" : 2,
    "n" : 1,
    "millis" : 0,
    "nYields" : 0,
    "nChunkSkips" : 0,
    "isMultiKey" : false,
    "indexOnly" : false,
    "indexBounds" : { }
    }
    

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20. create index
    > db.places.ensureIndex({name: 1})
    > db.places.find({name: 1}).explain()
    ...
    "cursor" : "BtreeCursor name_1",
    ...
    > db.places.ensureIndex({name: 1, zip: 1})
    ...
    "cursor" : "BtreeCursor name_1_zip_1",
    ....
    

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21. GEO Features
    place1 = {
    name : "10gen HQ",
    address : "578 Broadway 7th Floor",
    city : "New York",
    zip : "10012",
    tags : [ "business", "awesome" ],
    latlong : [40.0,72.0]
    }
    

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22. Adding A GEO Index
    place1 = {
    name : "10gen HQ",
    address : "578 Broadway 7th Floor",
    city : "New York",
    zip : "10012",
    tags : [ "business", "awesome" ],
    latlong : [40.0,72.0]
    }
    > db.places.ensureIndex({latlong : "2d"})
    

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23. Places v3
    place1 = {
    name : "10gen HQ",
    address : "578 Broadway 7th Floor",
    city : "New York",
    zip : "10012",
    tags : [ "business", "awesome" ],
    latlong : [40.0,72.0]
    }
    > db.places.ensureIndex({latlong : "2d"})
    > db.places.find({latlong:{$near:[40,70]}})
    

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24. Types of Queries
    Finding Places
    With Regular Expressions
    By Key:Value
    > db.places.find({latlong:{$near:[40,70]}})
    > db.places.find({name: /^typeAheadString/ })
    > db.posts.find({tags: "business" })
    

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25. Embedded Documents
    place1 = {
    name : "10gen HQ",
    address : "578 Broadway 7th Floor",
    city : "New York",
    zip : "10012",
    tags : [ "business", "awesome" ],
    latlong : [40.0,72.0],
    tips : [ { user : "ryan",
    time : 6/26/2010,
    tip : "stop by for office hours on
    Wednesdays from 4-6pm"},
    {.....}]
    }
    

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26. Application Goals
    Places Check ins
    (1)
    Q: Current location
    A: Places near location
    (2) Add user
    generated
    content
    (3) Record user
    checkins
    (4) Stats about
    checkins
    

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27. Updating Places
    Using Update to Add Tips
    > db.places.update({name:"10gen HQ"}, { $push :
    {tips: {user:"ranman", time:6/26/2010,
    tip:"stop by for office hours on Wednesdays
    from 4-6"}}}})
    

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28. Atomic Updates
    $set, $unset, $rename
    $push, $pop, $pull, $addToSet
    $inc
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    •
    

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29. Application Goals
    Places Check ins
    (1)
    Q: Current location
    A: Places near location
    (2) Add user
    generated
    content
    (3) Record user
    checkins
    (4) Stats about
    checkins
    

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30. Users
    checkins [] = ObjectId reference to check-in
    collection
    user1 = {
    name : "Randall",
    address : "randall@10gen.com",
    ...
    checkins : [4b97e62bf1d8c7152c9ccb74,
    5a20e62bf1d8c736ab]
    }
    

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31. Check-Ins
    checkin1 = {
    place : "10gen HQ",
    ts : 9/20/2010 10:12:00,
    userId :
    }
    

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32. Checking In
    Insert check in object
    [checkin collection]
    Update ($push) user object
    [user collection]
    •
    •
    2 Operations
    

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33. Querying Your Place
    Creating Your Index
    > db.checkins.ensureIndex({place:1,ts:1})
    > db.checkins.ensureIndex({ ts:1 })
    

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34. Application Goals
    Places Check ins
    (1)
    Q: Current location
    A: Places near location
    (2) Add user
    generated
    content
    (3) Record user
    checkins
    (4) Stats about
    checkins
    

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35. Simple Stats
    > db.checkins.find({place : "10gen HQ"})
    > db.checkins.find({place : "10gen
    HQ"}).sort({ts:-1}).limit(10)
    > db.checkins.find({place : "10gen HQ", ts:{ $gt:
    }}).limit()
    > db.checkins.find().sort({ts:-1}).limit(50)
    

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36. Stats With MapReduce
    mapFunc = function() { emit(this.place, 1); }
    reduceFunc = function(key, values) {
    return Array.sum(values);
    }
    db.checkins.mapReduce(mapFunc,reduceFunc, { query: {
    timestamp: {$gt:}}, out: result })
    result = [{_id:”10gen HQ”, value: 17}, {…..}, {….}]
    db.result.find({ value: {$gt: 15},
    _id: {$in: [….., ….., …..]}
    })
    

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37. Application Goals
    Places Check ins
    (1)
    Q: Current location
    A: Places near location
    (2) Add user
    generated
    content
    (3) Record user
    checkins
    (4) Stats about
    checkins
    : )
    

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38. MongoDB
    Deployments
    

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39. Replica Sets
    Primary
    Secondary
    Secondary
    Primary
    Secondary
    Arbiter
    Primary
    Secondary
    Secondary
    Secondary
    Secondary
    

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40. App
    Server
    App
    Server
    App
    Server
    Sharding
    MongoD
    MongoD
    MongoD
    MongoD
    MongoD
    MongoD
    MongoD
    MongoD
    MongoD
    MongoD
    MongoD
    MongoD
    ConfigD
    ConfigD
    ConfigD
    MongoS MongoS MongoS
    

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41. Try it for yourself at
    try.mongodb.org
    

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42. ranman.com
    github.com/ranman
    @jrhunt
    We’re hiring!! Engineers, Sales, Evangelist, Marketing & Support
    Contact us at jobs@10gen.com
    Questions?
    download at mongodb.org
    

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