![4
Document store
RDBMS MongoDB
Database Database
Table, View Collection
Row Document (JSON, BSON)
Column Field
Index Index
Join Embedded Document
Foreign Key Reference
Partition Shard
> db.user.findOne({age:39})
{
"_id" : ObjectId("5114e0bd42…"),
"first" : "John",
"last" : "Doe",
"age" : 39,
"interests" : [
"Reading",
"Mountain Biking ]
"favorites": {
"color": "Blue",
"sport": "Soccer"}
}](https://image.slidesharecdn.com/lecture401-230610064221-d29d7cad/85/lecture_40_1-pptx-4-320.jpg)
lecture_40_1.pptx
- 1. An introduction to MongoDB Rácz Gábor ELTE IK, 2013. febr. 10.
- 2. 2 NoSQL • Key-value • Graph database • Document-oriented • Column family
- 3. 3 Document store RDBMS MongoDB Database Database Table, View Collection Row Document (JSON, BSON) Column Field Index Index Join Embedded Document Foreign Key Reference Partition Shard
- 4. 4 Document store RDBMS MongoDB Database Database Table, View Collection Row Document (JSON, BSON) Column Field Index Index Join Embedded Document Foreign Key Reference Partition Shard > db.user.findOne({age:39}) { "_id" : ObjectId("5114e0bd42…"), "first" : "John", "last" : "Doe", "age" : 39, "interests" : [ "Reading", "Mountain Biking ] "favorites": { "color": "Blue", "sport": "Soccer"} }
- 5. 5 CRUD • Create • db.collection.insert( <document> ) • db.collection.save( <document> ) • db.collection.update( <query>, <update>, { upsert: true } ) • Read • db.collection.find( <query>, <projection> ) • db.collection.findOne( <query>, <projection> ) • Update • db.collection.update( <query>, <update>, <options> ) • Delete • db.collection.remove( <query>, <justOne> )
- 6. 6 CRUD example > db.user.insert({ first: "John", last : "Doe", age: 39 }) > db.user.find () { "_id" : ObjectId("51…"), "first" : "John", "last" : "Doe", "age" : 39 } > db.user.update( {"_id" : ObjectId("51…")}, { $set: { age: 40, salary: 7000} } ) > db.user.remove({ "first": /^J/ })
- 7. 7 Features • Document-Oriented storege • Full Index Support • Replication & High Availability • Auto-Sharding • Querying • Fast In-Place Updates • Map/Reduce Agile Scalable
- 8. 8 Memory Mapped Files • „A memory-mapped file is a segment of virtual memory which has been assigned a direct byte-for-byte correlation with some portion of a file or file-like resource.”1 • mmap() 1: http://en.wikipedia.org/wiki/Memory-mapped_file
- 9. 9 Replica Sets • Redundancy and Failover • Zero downtime for upgrades and maintaince • Master-slave replication • Strong Consistency • Delayed Consistency • Geospatial features Host1:10000 Host2:10001 Host3:10002 replica1 Client
- 10. 10 Sharding • Partition your data • Scale write throughput • Increase capacity • Auto-balancing Host1:10000 Host2:10010 Host3:20000 shard1 shard2 Host4:30000 configdb Client
- 12. 12 Map/Reduce db.collection.mapReduce( <mapfunction>, <reducefunction>, { out: <collection>, query: <>, sort: <>, limit: <number>, finalize: <function>, scope: <>, jsMode: <boolean>, verbose: <boolean> } ) var mapFunction1 = function() { emit(this.cust_id, this.price); }; var reduceFunction1 = function(keyCustId, valuesPrices) { return sum(valuesPrices); };
- 13. 13 Other features • Easy to install and use • Detailed documentation • Various APIs • JavaScript, Python, Ruby, Perl, Java, Java, Scala, C#, C++, Haskell, Erlang • Community • Open source
- 14. 14 Theory of noSQL: CAP CAP Theorem: satisfying all three at the same time is impossible A P • Many nodes • Nodes contain replicas of partitions of data • Consistency • all replicas contain the same version of data • Availability • system remains operational on failing nodes • Partition tolarence • multiple entry points • system remains operational on system split C
- 15. 15 Theory of noSQL: CAP CAP Theorem: satisfying all three at the same time is impossible A P • Many nodes • Nodes contain replicas of partitions of data • Consistency • all replicas contain the same version of data • Availability • system remains operational on failing nodes • Partition tolarence • multiple entry points • system remains operational on system split C
- 16. 16 ACID - BASE Pritchett, D.: BASE: An Acid Alternative (queue.acm.org/detail.cfm?id=1394128) •Atomicity •Consistency •Isolation •Durability •Basically Available (CP) •Soft-state •Eventually consistent (AP)
- 17. 17 THANK YOU