2. But First, A Little About Me My name’s Lee Theobald. Hello! Twitter: @Leesy Never updated blog: http://www.ltheobald.co.uk/ I’m a developer at a small search company in Cambridge called Open Objects.
4. NoSQL database The name is short for humongous Open source with development lead by 10Gen (http://www.10gen.com) Document Based Schema-less Highly Scalable MapReduce Replication & Auto Sharding
5. Document Store Data 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 Structure MongoDB 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 Cake db.recipes.find({ cooking_time: { “$gte”: 10, “$lt”: 30} }) db.recipes.findOne()
9. Some More Advanced Query Syntax Limiting db.find().limit(10); Skipping db.find( ).skip(5); Sorting db.find({…}).sort({cooking_time: “-1”}); Cursors var cur = db.find({…}).cursor() cur.forEach( function(x) { print(tojson(x)) });
10. MapReduce Great 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 Function Takes some input of the form of key/value pairs. Does something with that Returns 0 or more key/value pairs map = function() { if (!this.query) { return; } emit (this.query, {count: 1}); }
12. Reduce Function Takes the results from the map function Does something (normally combine the results) Produces output in key/value pairs reduce = function(key, values) { var count = 0; values.forEach(function(v) { count += v[‘count’]; } return {count: count;} }
13. Replica Sets Master/Slave configuration If your primary server goes down, one of the secondary ones takes over.
15. But Why Not Try It Yourself Download it at: http://www.mongodb.org Online tutorial at:http://www.mongodb.org/display/DOCS/Tutorial Some handy MongoDB sites: MongoDB Cookbook: http://cookbook.mongodb.org/ Kyle Banker’s blog: http://kylebanker.com/blog/
