Getting started with open-source CouchDB in NoSQL world (1)

NoSQL has now become a very popular topic in the IT industry. In this article, we will introduce you to the basic knowledge of CouchDB, a member of NoSQL, and take you into the world of NoSQL.

 

What is NoSQL?

NoSQL (short for not only SQL, also known as non-relational, or non-relational databases) does not use traditional relational database models, instead, we use models that store data such as key-value, document, column, graph, and xml. The reason for not using the traditional paradigm is that the way they store data has changed. For example, when you need to store invoice data, in the traditional relational data model, you need to design the table structure, and then convert it to an object using the server language, and then pass it to the client (this is the so-called ORM object ing). In NoSQL, you only need to save the invoice data. NoSQL can store new values without having to design tables and structures in advance. Of course, remember that NoSQL is not a silver bullet. If the data to be saved in your project does need a relational database model, you should always use a relational database.

Features of NoSQL

The emergence of NoSQL mainly aims to solve the problem of database read/write performance. With the emergence of a growing number of Web application systems, such as SNS and Weibo, a large amount of data needs to be read and written, in addition, distributed deployment is required, while traditional relational data models often need to connect multiple tables in the big data traffic and distributed environment, therefore, the performance is sometimes reduced, so NoSQL emphasizes "non-relational" data. NoSQL data storage does not require a fixed table structure and usually does not have connection operations. It has incomparable performance advantages over relational databases in terms of big data access.

In http://nosql-database.org/, the operators of nosqlare non-relational, distribution type, open source, and vertical expansion. Most NoSQL databases have the following features: Schema-free, convenient support for data redundancy, simple APIs, based on the eventually consistent and BASE principles (rather than ACID principles ). Currently, Google's BigTable and Amazon's Dynamo are very successful commercial NoSQL implementations. Some open-source NoSQL systems, such as Facebook's Cassandra and Apache's HBase, have also been widely recognized.