Java operations on MongoDBNoSQL Databases

I. Introduction MongoDB is a high-performance, open-source, non-relational (NoSQL) Document-type database that can be run directly with unzip without installation, it can be used in many scenarios to replace traditional relational databases or key-value storage methods. Developed Using C ++, Mongo provides the following features: * Set-oriented storage: Suitable for storage

I. Introduction MongoDB is a high-performance, open-source, non-relational (NoSQL) Document-type database that can be run directly with unzip without installation, it can be used in many scenarios to replace traditional relational databases or key/value storage methods. Mongo uses C ++ to enable the following features: * Set-oriented storage: Suitable for storage

I. Introduction
MongoDB is"Green"High-performance, open-source, non-relational (NoSQL) document-based databases can be run without installation and direct decompression (unzip, it can be used in many scenarios to replace traditional relational databases or key/value storage methods. Mongo uses C ++ to enable the following functions:
* Set-oriented storage: Suitable for storing objects and JSON data.
* Dynamic query: Mongo supports multiple Query expressions. Query commands use JSON tags to easily query embedded objects and arrays in a document.
* Complete indexing support: Includes embedded object and array of documents. The Query Optimizer of Mongo analyzes the query expression and generates an efficient query plan.
* Query monitoring: Mongo provides a monitoring tool to analyze the performance of database operations.
* Replication and automatic failover: The Mongo Database supports data replication between servers and master-slave mode and mutual replication between servers. The primary objective of replication is to provide redundancy and automatic failover.
* Efficient traditional storage: supports binary data and large objects (such as photos or images ).
* Automatic sharding to support cloud-level Scalability (in the early alpha stage): the automatic sharding function supports horizontal database clusters and allows you to dynamically add additional machines.

Ii. Scenario
MongoDB's main goal is to build a bridge between key/value storage and traditional RDBMS systems, combining the advantages of both. Mongo is suitable for the following scenarios:
* Website data: Mongo is ideal for real-time insertion, update, and query, as well as the replication and high scalability required for real-time website data storage.
* Cache: because of its high performance, Mongo is also suitable for serving as a cache layer for information infrastructure. After the system is restarted, the persistent cache layer established by Mongo can avoid data source overload at the lower layer.
* Large-sized and low-value data: traditional relational databases may be expensive to store some data. Previously, programmers often choose traditional files for storage.
* High scalability: Mongo is ideal for databases consisting of dozens or hundreds of servers. The Mongo roadmap contains built-in support for the MapReduce engine.
* The BSON data format of Mongo is very suitable for storing and querying object and JSON data.

Iii. Preparation
1. Download MongoDB latest version list http://www.mongodb.org/display/DOCS/Downloads,
Download the http://github.com/mongodb/mongo-java-driver/downloads of the required Jar driver package.

2. decompress the mongodb-linux-i686-1.2.4.tgz file you just downloaded.

3. Copy the decompressed mongodb directory to the directory you specified.

4. Create a data file directory mkdir-p/var/lib/mongodb/

5. Run the Mongodb service "./mongod-dbpath/var/lib/mongodb/-logpath/var/log/mongodb. log"
Specifies the directory where data files are stored, and specifies the directory where data log files are input.Thu Mar 25 22:18:52 waiting for connections on port 27017Indicates that the service is successfully started.

Iv. Example (CRUD/Java)
1. Create a connection
Mongo db = new Mongo (host, port );
DBCollection coll = db. getDB (dbName). getCollection ("testCollection ");
System. out. println (coll );

2. perform the operation
DBCollection coll = getConnection (host, port, dbName );
DBObject myDoc = coll. findOne ();
System. out. println (myDoc );

For the complete sample code, click here to download (Ref)

5. scalability
MongoDB can also adopt Sharding policies. Data routing is the role of mongos in MongoDB ,:

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-End-

Original article address: I would like to thank the original author for using MongoDB NoSQL databases in Java.