mongo an alternative database system. installing mongo we must install both the mongo database and...
TRANSCRIPT
MongoAn alternative database system
Installing Mongo
• We must install both the Mongo database and at least one GUI for managing Mongo
• See http://docs.mongodb.org/manual/installation • See http://www.mongodb.org/display/DOCS/Admin+UIs
What is Mongo?
• Document based • Focuses on clusters for extremely large scaling • Supports nested documents• Uses JavaScript for queries• No schema)
Basic Mongo concepts
• A database consists of collections• Which is more or less a table
• Collections are made up of documents • A lot like rows
• A document is made up of fields• A lot like columns
• There are also indices• There are also cursors
Mongo goals
• “Horizontal” scaling – • i.e., the cloud & simple servers• And no joins, effectively, pre-computed joins• Anti-normalization
• Fast• Avoid bottleneck of centralized schema• Near real-time data access• High availability
Implementation of Mongo
• C++• Heavy use of memory caching for read and write-through• Distributes by sharding
Applications of Mongo
• Medical records and other large document systems• Read heavy environments like analytics and mining• Partnered with relational databases• Relational for live data• Mongo for huge largely read only archives
• Online applications• Massively wide e-commerce
Using Mongo
• In bin folder• mongod for database• mongo for shell
• For data, it needs a directory called data on c: and a directory called db within data
• Commands• Global, like help• Db-specific, like db.x, where x is the collection• Db.x.help()
Tutorial from mongodb.pdf: The Little MongoDB Book
• Go to: http://openmymind.net/mongodb.pdf• First command: use learn• Second command: db.unicorns.insert({name: ‘Aurora’,
gender: ‘f’, weight: 450})• In other words, we can create a db and a collection
simply by saying they exist – no schema!
Query selectors
• Similar to an SQL program• Used for finding, counting, updating, and removing docs
from collections• {} is the null search and matches all documents• We could run: {gender:’f’}• {field1: value1, field2: value2} creates an ‘and’ operation• Also, less than, greater than, etc. (e.g., $gt)• $exists, $or
Updating data
• db.unicorns.update({name: ‘ro’}, {weight: 590})• Finds unicorn with that name and updates its weight
• Can also find and update records according to the keys mongo has assigned
• Note: mongo supports arrays as document fields
Documents
• Nested documents are supported• DBRef allows documents to reference each other• For the future? Full text search• Map reduce
You should get this
Other GUIs that are easy to install
• MongoVision (web based): http://code.google.com/p/mongo-vision/
• PHPMoAdmin (web based): http://www.phpmoadmin.com/ – this one is ugly, though!
• RockMongo (web based): http://rockmongo.com/
RockMongo is perhaps the best
Mongo tutorial: Assignment 8: Due Dec. 4
• Read the 33 page book• Follow the entire tutorial• Send an “I did it.” message for homework 8• Include your final document database (“db”) as a zipped
attachment• Include a screen snapshot of the GUI you used. (You can
do the project easily without a GUI, but it’s a good idea to get an idea of how they work.)
• Important: this material will be on the final.