This document introduces MongoDB, an open-source document database. It describes MongoDB as schema-less, highly scalable, and capable of replication and auto-sharding. Key features include storing data as JSON documents, a familiar database and collection structure, easy insertion and querying of documents, and aggregation of data using map-reduce functions. The document encourages readers to try MongoDB themselves by downloading it or exploring online tutorials.

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 JavaScript that
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.

14. Auto Sharding

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/