This document introduces MongoDB, an open-source document database. It describes MongoDB as schema-less, highly scalable, and storing data in JSON-like documents rather than tables. Documents can be inserted and queried using familiar syntax. MongoDB also supports more advanced features like map-reduce jobs, replica sets for high availability, and auto-sharding for horizontal scaling. The document encourages trying MongoDB yourself by downloading it or exploring online tutorials.

1. An introduction to

2. But First, A Little About MeMy name’s Lee Theobald. Hello!Twitter: @LeesyNever updated blog: http://www.ltheobald.co.uk/I’m a developer at a small search company in Cambridge called Open Objects.

3. So what is MongoDB?

4. NoSQL databaseThe name is short for humongousOpen source with development lead by 10Gen (http://www.10gen.com)Document BasedSchema-lessHighly ScalableMapReduceReplication & Auto Sharding

5. Document StoreData is stored in the form of JSON data.{"_id" : ObjectId("4ccbfc75bd163019417c27f8"),"title": “Hello World! ","author": {"firstname": "Joe","lastname": "Bloggs" },"tags": ["test", "foo", "bar"]}

6. Familiar StructureMongoDB instances contain a number of databases which in turn contain a number of collections.Think of MySQL with it’s databases & tables.But collections can also be nested. E.g.customer_a(Database)logs_201009 (Collection)top_queries(Collection)

7. Inserts – Easy As Pie!use cookbook;db.desserts.save({ name: "Cherry Pie", ingredients: ["cherries", "pie"],cooking_time: 30});

8. Searching – A Piece Of Cakedb.recipes.find({cooking_time: { “$gte”: 10, “$lt”: 30}})db.recipes.findOne()

9. Some More Advanced Query SyntaxLimitingdb.find().limit(10);Skippingdb.find( ).skip(5);Sortingdb.find({…}).sort({cooking_time: “-1”});Cursorsvar cur = db.find({…}).cursor()cur.forEach( function(x) { print(tojson(x)) });

10. MapReduceGreat way of doing bulk manipulation or aggregation.2 or 3 functions written in JavaScriptthat execute on the server.An example use could be generating a list of top queries from some search logs.

11. Map FunctionTakes some input of the form of key/value pairs.Does something with thatReturns 0 or more key/value pairsmap = function() { if (!this.query) { return; } emit (this.query, {count: 1});}

12. Reduce FunctionTakes the results from the map functionDoes something (normally combine the results)Produces output in key/value pairsreduce = function(key, values) {var count = 0;values.forEach(function(v) { count += v[‘count’]; } return {count: count;}}

13. Replica SetsMaster/Slave configurationIf your primary server goes down, one of the secondary ones takes over.

14. Auto Sharding

15. But Why Not Try It YourselfDownload it at: http://www.mongodb.orgOnline tutorial at:http://www.mongodb.org/display/DOCS/TutorialSome handy MongoDB sites:MongoDB Cookbook: http://cookbook.mongodb.org/Kyle Banker’s blog: http://kylebanker.com/blog/

16. Thanks For Listening.Any (easy)Questions?