w2_2_MongoDB

MongoDB
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* Databases
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-> Databases are used to store structured information;
-> Databases support various operations on the data
i. query
ii. insert
iii. update
iv. delete;

-> SQL(Structured Query Language) based on relational databases, have been very popular means of storing data;
-> NoSQL databases are increasingly becoming popular to address sql database challenges;

NoSQL Databases 
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4 different broad categories
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a. Document databases (MongoDB); JSON document; -> document -> collection -> database
b. Key-value databases; (Redis)
c. Column-family databases (Cassandra)
d. Graph databases (Neo4J)

Why NoSQL?
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a. Scalability (the capacity to be changed in size or scale, o be used or produced in a range of capabilities)
  i. Availability
  ii. Consistency
  iii. Partition tolerance
b. Ease of Deployment
  - No object-relation mapping required; (map the relatinal data into objects that can be used in the code);

MongoDB
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-> Documentbased Database;
-> Mongo Server can support multiple databases simultaneously;
-> Database consists of a set of collections;
-> A collection is a set of document;
-> Document - JSON document;

MongoDB Format
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-> When Mongo stores the data on the disk, it stores it in a BSON (Binary JSON format);
  - Supports the length prefix on each value; easy to skip over a field;
  - Information about the type of a field value;
  - Additional primitives types not supported by raw JSON like UTC date time, raw binary, and OjectId are allowed in BSON;

MongoDB ObjectId
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-> Every document in Mongo must have an "_id" field that is unique, could be created by default;
-> ObjectId is a 12 byte field: |Timestamp (4) | Machine ID (3) | Proc. ID(2) | Increment (3) |
id.getTimestamp() -> returns the timestamp in ISO Date format;


https://www.mongodb.com/
mongod --dbpath=data
mongo
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32-bit system;
download mongodb compatible with 32-bit operating system;
-> create a data/db folder  as well as mongodb folder;
(within the MongoDB\Server\3.2\bin)
->  cmd -> mongod --storageEngine=mmapv1 --dbpath=C:\data\db
-> cmd -> mongo.exe


within the installed folder
cmd1: mongod --storageEngine=mmapv1 --dbpath=C:\data\db
cmd2: mongo.exe

Instructions
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i.  db
ii. use conFusion
iii.db
iv. db.help()
v. db.dishes.insert({ name: "Uthapizza", description: "Test" });
vi. db.dishes.find().pretty();
vii.var id = new ObjectId();
     id.getTimestamp();