Building Web Applications with MongoDB: An Introduction

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.

Transcript

1. http://mongodb.org http://10gen.com Building applications with MongoDB – An introduction Roger Bodamer roger@10gen.com @rogerb
2. Today`s Talk • MongoDB: Data modeling, queries, geospatial, updates, map reduce • Using a location-based app as an example • Example Works in MongoDB JS shell
3. Design • Want to build an app where users can check in to a location • Leave notes or comments about that location • Approach: • Decide requirements, and then design documents
4. Requirements Places (1) Q: Current location A: Places near location (2) Add user generated comments, content
5. Requirements Places Check ins (1) Q: Current location A: Places near location (2) Add user generated comments, content (3) Record user checkins (4) Stats about checkins
6. Terminology RDBMS Mongo Table, View Collection Row(s) JSON Document Index Index Join Embedded Document Partition Shard Partition Key Shard Key
7. Documents { _id : ObjectId("4c4ba5c0672c685e5e8aabf3"), author : "roger", date : "Sat Jul 24 2010 19:47:11 GMT-0700 (PDT)", text : ”MongoSF", tags : [ ”San Francisco", ”MongoDB" ] } Notes: - _id is unique, but can be anything you’d like
8. Collections doc1, doc2, doc3 Places Users Checkins doc3, doc4, doc5 doc6, doc7, doc8
9. place1 = { name: "10gen HQz, 
 address: z134 5th Avenue 3rd Floorz,
 city: "New Yorkz,
 zip: "10011z
 } Places v1
10. place1 = { name: "10gen HQz, 
 address: z134 5th Avenue 3rd Floorz,
 city: "New Yorkz,
 zip: "10011z
 } db.places.find({zip:”10011”}).limit(10) Places v1
11. place1 = { name: "10gen HQz, 
 address: "17 West 18th Street 8th Floorz,
 city: "New Yorkz,
 zip: "10011z, tags: [lbusinessz, lrecommendedz]
 } Places v2
12. place1 = { name: "10gen HQz, 
 address: "17 West 18th Street 8th Floorz,
 city: "New Yorkz,
 zip: "10011z, tags: [lbusinessz, lrecommendedz]
 } db.places.find({zip:”10011”, tags:”business”}) Places v2
13. place1 = { name: "10gen HQz, 
 address: "17 West 18th Street 8th Floorz,
 city: "New Yorkz,
 zip: "10011z, tags: [lbusinessz, lcool placez], latlong: [40.0,72.0]
 } Places v3
14. place1 = { name: "10gen HQz, 
 address: "17 West 18th Street 8th Floorz,
 city: "New Yorkz,
 zip: "10011z, tags: [lbusinessz, lcool placez], latlong: [40.0,72.0]
 } db.places.ensureIndex({latlong:”2d”}) Places v3
15. place1 = { name: "10gen HQz, 
 address: "17 West 18th Street 8th Floorz,
 city: "New Yorkz,
 zip: "10011z, tags: [lbusinessz, lcool placez], latlong: [40.0,72.0]
 } db.places.ensureIndex({latlong:”2d”}) db.places.find({latlong:{$near:[40,70]}}) Places v3
16. place1 = { name: "10gen HQz, 
 address: "17 West 18th Street 8th Floorz,
 city: "New Yorkz,
 zip: "10011z,
 latlong: [40.0,72.0], tags: [lbusinessz, lcool placez],
 tips: [ {user:"nosh", time:6/26/2010, tip:"stop by for office hours on Wednesdays from 4-6pm"}, {.....}, ]
 } Places v4
17. Creating your indexes db.places.ensureIndex({tags:1}) db.places.ensureIndex({name:1}) db.places.ensureIndex({latlong:”2d”}) Finding places: db.places.find({latlong:{$near:[40,70]}}) With regular expressions: db.places.find({name: /^typeaheadstring/) By tag: db.places.find({tags: lbusinessz}) Querying your Places
18. Initial data load: db.places.insert(place1) Using update to Add tips: db.places.update({name:"10gen HQ"}, {$push :{tips: {user:"nosh", time:6/26/2010, tip:"stop by for office hours on Wednesdays from 4-6"}}}}
19. Application Goals Places Check ins (1) Q: Current location A: Places near location (2) Add user generated content (3) Record user checkins (4) Stats about checkins
20. user1 = { name: lnoshz email: lnosh@10gen.comz, . . . checkins: [{ place: l10gen HQz, ts: 9/20/2010 10:12:00, userId: <objectid of user>}, … ]
 } checkins [] = ObjectId reference to checkin collection Users
21. user1 = { name: lnoshz email: lnosh@10gen.comz, . . . checkins: [4b97e62bf1d8c7152c9ccb74, 5a20e62bf1d8c736ab]
 } checkins [] = ObjectId reference to checkin collection Alternative
22. checkin1 = { place: l10gen HQz, ts: 9/20/2010 10:12:00, userId: <objectid of user>
 } Check-in = 2 ops Insert check in object [checkin collection] Update ($push) user object [user collection] Indexes: db.checkins.ensureIndex({place:1, ts:1}) db.checkins.ensureIndex({ts:1}) Checkins
23. Simple Stats db.checkins.find({place: l10gen HQz) db.checkins.find({place: l10gen HQz}) .sort({ts:-1}).limit(10) db.checkins.find({place: l10gen HQz, ts: {$gt: midnight}}).count()
24. Stats with MapReduce mapFunc = function() { emit(this.place, 1);} reduceFunc = function(key, values) { return Array.sum(values); } db.checkins.mapReduce(mapFunc,reduceFunc, {query: {timestamp: {$gt:nowminus3hrs}}, out: lresultz}) [{_id:z10gen HQz, value: 17}, {…..}, {….}] result.find({ value: {$gt: 15}, _id: {$in: [….., ….., …..]} })
25. 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
26. Single Master Deployments Primary/Master Secondary/Slave • Configure as a replica set for automated failover • Add more secondaries to scale reads
27. Auto Sharded Deployment Primary/Master Secondary/Slave MongoS • Autosharding distributes data among two or more replica sets • Mongo Config Server(s) handles distribution & balancing • Transparent to applications Mongo Config
28. Use Cases • RDBMS replacement for high-traffic web applications • Content Management-type applications • Real-time analytics • High-speed data logging Web 2.0, Media, SaaS, Gaming, Finance, Telecom, Healthcare
29. http://mongodb.org http://10gen.com We are hiring! @mongodb roger@10gen.com @rogerb
30. MongoDB in Production