Building Your First MongoDB Application

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. Building your First MongoDB Application Rick Copeland @rick446 http://arborian.com Saturday, June 9, 12
2. Who am I? • Now a consultant, but formerly... • Software engineer at SourceForge • Author of Essential SQLAlchemy • Primarily code Python Saturday, June 9, 12
3. What will you learn here? Saturday, June 9, 12
4. What will you learn here? • Data Modeling Saturday, June 9, 12
5. What will you learn here? • Data Modeling • Queries Saturday, June 9, 12
6. What will you learn here? • Data Modeling • Queries • Geospatial indexing Saturday, June 9, 12
7. What will you learn here? • Data Modeling • Queries • Geospatial indexing • Updates Saturday, June 9, 12
8. What will you learn here? • Data Modeling • Queries • Geospatial indexing • Updates • Map/Reduce Saturday, June 9, 12
9. What will you learn here? • Data Modeling • Queries • Geospatial indexing • Updates • Map/Reduce • Deployment and Scaling Concerns Saturday, June 9, 12
10. What will you learn here? • Data Modeling • Queries • Geospatial indexing • Updates • Map/Reduce • Deployment and Scaling Concerns • Why MongoDB? Saturday, June 9, 12
11. Our Application • Users can create different locations • Users can “check in” to these locations • Users can see who else is checked in • Let’s call it ThreeTriangles (3tri) Saturday, June 9, 12
12. 3tri Operations Places Checkins User-generated content Find nearby places Record checkins Checkin Stats Saturday, June 9, 12
13. MongoDB Terminology Relational MongoDB Database Database Table Collection Index Index Row Document Column Field Saturday, June 9, 12
14. Documents? doc1 = {! _id: ObjectId('4b97e62bf1d8c7152c9ccb74'), key1: value1,! key2: value2, key3: {..., ..., ...}, key4: [..., ..., ] } Saturday, June 9, 12
15. Collections • No schema enforcement • Per-collection... • Querying • Indexing • Updating • Sharding doc1,doc2,... doc5,doc6,... doc8,doc9,... Places Users Checkins Saturday, June 9, 12
16. Places v1 place1 = {! name: "Blake Hotel",! address: "555 South McDowell Street", city: "Charlotte", zip: "28204"} db.places.find({zip:"28204"}).limit(10) Saturday, June 9, 12
17. Places v2 place2 = { name: "Blake Hotel",! address: "555 South McDowell Street", city: "Charlotte", zip: "28204", tags: ["hotel", "recommended"]} db.places.find({ zip: "28204", tags: "hotel"}).limit(10) Saturday, June 9, 12
18. Places v3 place3 = { name: "Blake Hotel",! address: "555 South McDowell Street", city: "Charlotte", zip: "28204", tags: ["hotel", "recommended"], latlon: [ 35.21, 80.83 ] } db.places.ensureIndex({latlong:"2d"}) db.places.find({latlong:{$near:[35,80]}}) Saturday, June 9, 12
19. Places v4 place4 = { name: "Blake Hotel",! address: "555 South McDowell Street", city: "Charlotte", zip: "28204", tags: ["hotel", "recommended"], latlon: [ 35.21, 80.83 ], tips: [ { user: "rick", time: ISODateTime(...), tip: "Come learn about #self2012"}, { ... }, { ... } ] } Saturday, June 9, 12
20. Some Queries /* First, some indexes */ db.places.ensureIndex({tags:1}) db.places.ensureIndex({name:1}) db.places.ensureIndex({latlong:"2d"}) /* Find places */ db.places.find({latlong:{$near:[40,70]}}) /* Regex searching */ db.places.find({name: /^typeaheadstring/) /* Searching arrays */ db.places.find({tags: "business"}) Saturday, June 9, 12
21. Inserting and updating /* Initial data load */ db.places.insert([place1, place2, ...]) /* Update-in-place */ db.places.update( { name:"Blake Hotel" }, { $push : { tips: { user: "rick", time: ISODateTime(...), tip: "Come learn about #self2012" } } } ) Saturday, June 9, 12
22. 3tri Operations Places Checkins User-generated content Find nearby places Record checkins Checkin Stats Saturday, June 9, 12
23. Users user1 = { name: "rick", email: "rick@arborian.com", ... checkins: [ ObjectId('4b97e62bf1d8c7152c9ccb74'), ... ] } /* checkins [] = references checkin collection _id field */ Saturday, June 9, 12
24. Checkins db.checkins.ensureIndex({place:1, ts:1}) db.checkins.ensureIndex({ts:1}) checkin1 = { place: { id: ObjectId(...), name: "Blake Hotel" }, ts: ISODateTime(...), user: { id: ObjectId(...), name: "rick" } } Saturday, June 9, 12
25. Atomic Updates • $set • $unset • $rename • $push • $pushAll • $pop • $pull • $pullAll • $addToSet • $inc • $bit Saturday, June 9, 12
26. 3tri Operations Places Checkins User-generated content Find nearby places Record checkins Checkin Stats Saturday, June 9, 12
27. Simple Statistics /* All checkins */ db.checkins.find({"place.name": "Blake Hotel"}) /* Last 10 checkins */ db.checkins.find({"place.name": "Blake Hotel"}) .sort({ts:-1}).limit(10) /* Number of checkins today */ db.checkins.find( { "place.name": "Blake Hotel", ts: { $gt: ISODateTime(...)} }) .count() Saturday, June 9, 12
28. MapReduce mapFunc = function() { emit(this.place.name, 1); } reduceFunc = function(key, values) { return Array.sum(values); } res = db.checkins.mapReduce( mapFunc, reduceFunc, ! { query: { ts: { $gt: nowminus3hrs } } out: {inline: 1} }) res.results = [ {_id:"Blake Hotel", value: 17}, ...] Saturday, June 9, 12
29. Deployment and Scaling Options Saturday, June 9, 12
30. Single Master Deployment Primary Secondary Secondary Read / Write Read Read Saturday, June 9, 12
31. Auto-Sharding Shard 1 (0..10) Primary Secondary Secondary Shard 2 (10..20) Primary Secondary Secondary Shard 3 (20..30) Primary Secondary Secondary Config Saturday, June 9, 12
32. Use Cases • Replace RDBMS for high-traffic web applications • CMS-style applications • Social and mobile applications • Real-time analytics, high-speed logging • Maybe not double-entry bookkeeping Saturday, June 9, 12
33. What do you give up? • No multi-document atomic operations (i.e. transactions) • No server-side JOINs • No referential integrity constraints between documents • Data model is typically tied to query patterns (less flexible than relational DBs) Saturday, June 9, 12
34. Questions? Please rate this talk at http://svy.mk/L3jM7f Interested in training? http://Arborian.com/training MongoDB Info & Downloads: http://mongodb.org Rick Copeland @rick446 http://arborian.com Saturday, June 9, 12