Brief description

MongoDB is written in C document-oriented NoSQL database management system open source, does not require the description of the table schema (schemaless).

MongoDB has the following levels of reporting:

  1. The document is a JSON object with an arbitrary number of fields. Fields can store both proste value to voennye objects and arrays.
  2. Collection (table)- the same type documents are stored in separate collections. The documents in the collection can be proindeksirovany. Access dokumentu possible by key and value fields.
  3. Database - a set of collections.

Support MongoDB is implemented for most programming languages:

  • C;
  • C ;
  • C#;
  • Java;
  • Node.js;
  • Perl;
  • PHP;
  • Python;
  • Ruby;
  • Scala.

Differences MongoDB from relational databases:

  • Not supported TransAsia. Atomicity is guaranteed only at the level of the whole document, that is, a partial document updates cannot occur. The absence of a mechanism of isolation» qmo. Any data that is read by the same client in parallel, which can be changed by another client.

The benefits of MongoDB relational database before:

  • Supports horizontal scaling with replication data. Data can be stored on an arbitrary number of servers. Replication provides fault-tolerance support functions at the output nodes of the system.
  • Data storage format (document) is close to the format of data representation in programming languages (objects) does not require complex and expensive queries to get the desired object.
  • Support operations for MapReduce massively parallel data processing.

Presentation

Software

Laboratory work and practical tasks

To install mongoDB the easiest to use docker image with MongoDB.

Start the server by the command:

docker run --name mongodb -p 27017:27017 -d mongo

To work with the mongo server in containere it is recommended to run within the running container mongo-shell command:

docker exec -it mongodb mongo

As practical tasks for laboratory work you can use of the Task for the laboratory work 5 MongoDB. On this page is given as link to the test dataset, and a list of tasks for you to perform operations on these data sets.

Examples

Examples of the CRUD and aggregation operations specified in the previous section, data sets, please see pages:

Opportunities for certification

Go

Переведено сервисом «Яндекс.Переводчик» http://translate.yandex.ru