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SQL and NoSQL databases

MongoDB

developers often consider MongoDB to be the main choice when building a data-driven application. However, many alternatives may provide better solutions.

This repository was built with the intention of exploring various database options to connect to Node.js backend such as:

  1. MongoDB (Users management, Data Seeding, Schema Generation) dockerDefaultPort: 27017
  2. Redis (Session management, Set up Items services and basket services)dockerDefaultPort: 6379
  3. MySQL. (Orders management, check-out services and review database relational links) dockerDefaultPort: 3306

CRUD operations was built by using JS classes and instances.

Databases installed by pulling docker image from hub

Mongoose

A schema-based solution to modeling application data in MongoDB. It includes built-in type casting, validation, query building... designed to work in an asynchronous environment. Mongoose belongs to "Object Document Mapper (ODM)" category of the tech stack, while Sequelize can be primarily classified under "Object Relational Mapper (ORM)".

Redis

An important subset of NoSQL databases are key value stores. While key value stores are very limited, they're also very powerful and fast. Redis basically stores the data in memory which makes it blazingly fast but also, the data might get lost, if you kill the Redis process. Redis is often used as a cache. It can also be used as a storage when the consistency requirements are not high.

ioRedis

A robust, performance-focused and full-featured Redis client for Node.js. Unlike NodeRedis, ioRedis supports promises

connect-Redis

It provides Redis session storage for Express.

Redis methods (commands) are referred to the comprehensive doc at: Redis Commands

MySQL

When to use relational databases:

  • When there are multiple different entities that are in some way, related.
  • When the database needs to stay in a consistent state.
  • When the database should also enforce this consistency no matter from which application it is accessed.

Example in this app: Basket ↔ Order ↔ OrderItems

Unlike Redis and MongoDB, relational databases like MySQL rely on static table structures so-called 'schemas' to be defined directly inside the database.

Sequelize

A promise-based ORM for Node.js and io.js. It supports PostgreSQL, MySQL, MariaDB, SQLite and MSSQL

Reverse Engineering in MySQL

A powerful tool helps create a visual representation of relationship between different tables. With MySQL Workbench, you can reverse-engineer a database using a MySQL create script or you can connect to a live MySQL server and import a single database or a number of databases.

SQL Transaction: a single unit of work applied to a relational database

  • It is a sequence of ordered operations performed on the database.
  • SQL statements are used to execute tasks such as update data or get data from a database.
  • The SQL statements of a transaction will either Commit or Rollback using a rollback statement.
  • The transaction comprises of two results, they are either success or failure.