HadoopMongoDB

What is MongoDB?

MongoDB Overview:

  • MongoDB is an open source database
  • Developed by 10gen and now named as MongoDB
  • It is an agile database and allows schemas to change quickly with very less impact on application.no DDL and the changes can be done from application layer.
  • Scalable,High performance and always available
  • Allow Caching
  • Handle failover automatically  and easy to replicate

What is MongoDB?

  • It is a open source database
  • Document storage is in JSON(JavaScriptObjectNotation) format
  • it is stored in database in Binary format
  • it is written in C++ so it is light weight
  • Easy to use
  • High indexing support
  • Data is distributed in multiple nodes,so it is always available and replication is easy
  • Data distribution is automatic
  • Easy interface to query database
  • MongoDB has its own Mapreduce framework
  • Uses Grid FS to store large files ex: video,audio files etc and gives the provision to save these high volume data in distributed manner

Terminology between RDBMS and MongoDB:

RDBMS MongoDB
Database Database
Table Collection
Tuple/Row Document(JSON)
Column/Attribute Field
Table Join Embedded Document(Parent and child documents)
Primary key Primary Key(Key_id by MongoDB)
mysql/sqlplus mongo

Production environment for MongoDB?

  • MongoDB has large no of clusters and each node is called Shard.
  • Shards are nothing but the actual nodes containing the actual data
  • The query are getting routed through Mongos from app server to MongoDB
  • Mongos contacts the configuration file to see the meta data information on clusters before getting routed to MongoDB clusters

MongoDB CRUD operation:

  • MongoDB provides functionalities for reading and manipulating data
  • CRUD stands for Create,Read,Update and Delete operations

Data operations:

  • Query
    • Read
  • Data Modification
    • Create
    • Update
    • Delete

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