MongoDB
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This document provides an overview of non-relational databases and MongoDB. It discusses the advantages of non-SQL databases like scalability and flexibility compared to RDBMS. It also covers MongoDB features like document-oriented data structure, dynamic queries, indexing, replication and sharding. The document demonstrates basic MongoDB operations in Ruby like connecting to a database, inserting and querying documents.
![Storage (BSON)
{ author: 'joe',
created: Date('03-28-2009'),
title: 'Yet another blog post',
text: 'Here is the text...',
tags: [ 'example', 'joe' ],
comments: [ { author: 'jim', comment: 'I disagree' },
{ author: 'nancy', comment: 'Good post' }
]
}](https://image.slidesharecdn.com/mongodbmy-091019010509-phpapp01/85/MongoDB-15-320.jpg)
![Querying 2
• $in, $nin, $all, $ne, $gt, $gte, $lt, $lte, $size, $where
• :fields (like :select in active record)
• :limit, :offset for pagination
• :sort ascending or descending [[‘foo’, 1], [‘bar’, -1]]
• count and group (uses map/reduce)](https://image.slidesharecdn.com/mongodbmy-091019010509-phpapp01/85/MongoDB-18-320.jpg)
MongoDB
- 1. nonSQL databases alexey gaziev
- 2. RDBMS • Great for many apps • Shortcomings • Scalability • Flexibility
- 3. Other DBMS • Flat file • Hierarchical • Network • Document-oriented • Object-oriented
- 4. CAP Theorem Pick two С A • Consistency • Availability P • Tolerance to network Partitions http://www.cs.berkeley.edu/~brewer/cs262b-2004/PODC-keynote.pdf
- 5. ACID & BASE • Atomicity • Basically Available • Consistency • Soft state • Isolation • Eventually consistent • Durability
- 6. ACID vs. BASE ACID BASE • Strong consistency • Weak consistency • Isolation • Availability first • Focus on “commit” • Best effort • Nested transactions • Approximate answers • Availability? • Agressive (optimistic) • Conservative • Simpler! • Difficult evolution • Faster (schema) • Easier evolution
- 8. Scalability & Intro Performance memcached Key/Values store RDBMS Depth of Functionality
- 9. Features • Collection oriented storage: easy storage of object/ JSON -style data • Dynamic queries • Full index support, including on inner objects and embedded arrays • Query profiling • Replication and fail-over support • Efficient storage of binary data including large objects (e.g. photos and videos) • Auto-sharding for cloud-level scalability (currently in alpha) • Commercial support available
- 10. Great for • Websites • Caching • High volume, low value • High scalability • Storage of program objects and json
- 11. Not as great for • Highly transactional • Ad-hoc business intelligence • Problems requiring SQL
- 12. Installation
- 13. Collection • Think table, but with no schema • For grouping into smaller query sets (speed) • Each top entity in your app would have its own collection (users, articles, etc.) • Full index support
- 14. Document • Stored in collection, think record or row • Can have _id key that works like primary key in MySQL • Two options for relationships: subdocument or db reference
- 15. Storage (BSON) { author: 'joe', created: Date('03-28-2009'), title: 'Yet another blog post', text: 'Here is the text...', tags: [ 'example', 'joe' ], comments: [ { author: 'jim', comment: 'I disagree' }, { author: 'nancy', comment: 'Good post' } ] }
- 16. Basics $ bin/mongod & $ bin/mongo ... > use mydb > j = { name: "mongo"}; {"name" : "mongo"} > t = { x : 3 }; { "x" : 3 } > db.things.save(j); > db.things.save(t); > db.things.find(); in cursor for : DBQuery: example.things -> {"name" : "mongo" , "_id" : "497cf60751712cf7758+dbb"} {"x" : 3 , "_id" : "497cf61651712cf7758+dbc"} >
- 17. Querying • db.collection.find({‘first_name’: ‘John’}) # finds all Johns • db.collection.find({‘first_name’: /^J/}) # regex • db.collection.find_first({‘_id’:1}) # finds first with _id of 1 • db.collection.find({‘age’: {‘$gt’: 21}}) # finds possible drinkers • db.collection.find({‘author.first_name’:‘John’}) # subdocument • db.collection.find({$where:‘this.age >= 6 && this.age <= 18’})
- 18. Querying 2 • $in, $nin, $all, $ne, $gt, $gte, $lt, $lte, $size, $where • :fields (like :select in active record) • :limit, :offset for pagination • :sort ascending or descending [[‘foo’, 1], [‘bar’, -1]] • count and group (uses map/reduce)
- 19. Dynamic querying
- 20. Ruby support • mongo-ruby-driver • Pure Ruby, with optional C extension • MongoRecord • ORM like functionality • Other mappers
- 21. Ruby basics • Connect: • db = Mongo.new.db(‘my-database’) • coll = db.collection(‘players’) • Insert: • coll.insert (“name” => “mike”, “age” => ... • Query: • coll.find (“age” => 35)
- 22. Grid FS • File storage in MongoDB • IO-like API for Ruby
- 23. Other cool stuff • Capped collections • Upserts • Multikeys
- 24. Resources • http://spitfiresky.com/blog/recap-of-my-sdruby- presentation-on-mongodb.html • http://railstips.org/2009/6/3/what-if-a-key- value-store-mated-with-a-relational-database- system • http://www.mongodb.org/display/DOCS/ Production+Deployments • http://www.mongohq.com/home
- 25. Resources 2 • http://api.mongodb.org/ruby/0.15.1/index.html • http://www.engineyard.com/blog/2009/ mongodb-a-light-in-the-darkness-key-value- stores-part-5 • http://queue.acm.org/detail.cfm?id=1394128
- 26. thanks!