Introduction to MongoDB

1. http://mongodb.org
http://10gen.com
Introduction to mongoDB
Shankar Kamble

2. Today’s Talk
• Idea about mongoDB , mongo shell
• CRUD operation of mongo i.e.Insert,Update,Delete.
• Introduction to findOne, Querying using field
selection,$ gt,$ lt
• Using regexes,$ exists, $ type,$ or,$ and,$ in,$ all
• Index in mongoDB.
• Aggregation in mongoDB.

3. What is MongoDB?
• Scalable, High-Performance, Open-source.
• Document Oriented Database
• Built for Speed.
• Full Index Support for High Performance.
• Replication and Failover for High Availability.

4. MongoDB
• Map / Reduce for Aggregation
• Auto Sharding for Easy Scalability
• Platforms 32/64 bit Windows Linux, Mac OS-X,
FreeBSD, Solaris
• Language drivers for:
– Ruby / Ruby-on-Rails
– Java
– C#
– JavaScript
– C / C++
– Node.js
– Erlang Python, Perl others..... and much more ! ..

5. • No Joins + No multi-row transactions
– Horizontally Scalable
• Built-in Replication
–Easy to configure
–Automatic failover when using Replica Sets
Fast read/write operation
Shard for scalability, replicate for availability
Why MongoDB:- Scalability / Availability /
Performance

7. In Production
http://www.mongodb.org/about/production-deployments/

8. Terminology
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"}
}

9. BSON
• JSON has powerful, but limited set of datatypes
–Mongo extends datatypes with Date, Int types, Id, …
• MongoDB stores data in BSON
• BSON is a binary representation of JSON

10. http://www.mongodb.org/downloads
Installation

11. MongoDB Package
Components

12. The Mongo
Shell
>mongo
>help()
>show dbs
>use <dbname>
>show collections
>db.collectionName.findOne()
>db.collectionName.find()
>db.help()
>db.collectionName.help()

13. CRUD Operations

14. Insert
→
See that new “_id” field? We’ll discuss that
later.

15. Update

16. Remove

17. FindOne

18. In Clause

19. Sorting? Limiting? Skipping?
sort(), limit(), skip()

20. Sorting?
1 = true, 1 = asc, 1 = include
-1 = false, -1 = desc, -1 = exclude

21. Sorting?Limiting?

22. Sorting?Limiting?Skipping?

23. Aggregation

24. count()

25. distinct ()

26. group()
db.article.aggregate(
{ $group : {
_id : "$author",
docsPerAuthor : { $sum : 1 },
viewsPerAuthor : { $sum : "$pageViews" }
}}
);
This aggregation pipeline groups by the author field and computes two fields, the
first docsPerAuthor is a counter field that increments by one for each document
with a given author field using the $sum function. The viewsPerAuthor field is the
sum of all of the pageViews fields in the documents for each group.

27. Index

28. Creating your indexes
db.locations.ensureIndex({tags:1})
db.locations.ensureIndex({name:1})
db.locations.ensureIndex({latlong:”2d”})
Index

29. explain()
explain()
explain will return information about the indexes used for the query (if any)
and stats about timing and the number of documents scanned.
db.users.find({"name":"user0"}).explain()
{
"cursor" : "BtreeCursor name_1",
"nscanned" : 1,
"nscannedObjects" : 1,
"n" : 1,
"millis" : 0,
"nYields" : 0,
"nChunkSkips" : 0,
"isMultiKey" : false,
"indexOnly" : false,
"indexBounds" : {
"name" : [
[
"user0",
"user0"
]
]
}
}

30. Sql Vs MongoDB
Click
Here:http://docs.mongodb.org/manual/reference/sql-
comparison/

31. Summary
• MongoDB is good
-Stores objects.
-Felxible semi-structured design
-Store big data
-Embedded documents to eliminates join.
• Mongodb is bad
-No multi-document query
-No Support for transactions

32. http://mongodb.org
http://10gen.com
-Questions