The document database of the technical characteristics of NoSQL database

Today, cloud computing practitioners are not unfamiliar with the word nosql, although many technicians have long been engaged in http://www.aliyun.com/zixun/aggregation/22.html "> relational database work, But now they are full of anticipation for NoSQL technology. The transition from relational to NoSQL databases is definitely a big change to be considered for businesses. This involves not only the changes in software, but also the conceptual changes in data storage.

Couchdb expert and author Bradley Holt that NoSQL is not an anti-SQL campaign, and choosing the most appropriate tool for the corresponding job is the right model.

Most non-relational databases have fast and scalable features. By discarding relational storage models and schemas, relational databases can be detached from the constraints imposed by tightly coupled architectures. The application also eliminates the need to link data from tables in the database.

Document databases such as MongoDB and Couchdb and Ravendb (Ravendb are written based on the Mocrosoft. NET framework) typically provide data through HTTP in addition to certain transformations, The data is then stored as a JSON (JavaScript Object notation)-formatted document and provides API interfaces for multiple languages. These three open source document databases make simplicity, speed, and scalability an important indicator of their design. The creator of Ravendb, Ayende Rahien, said that "Ravendb was designed to write and read quickly."

Today, NoSQL and document databases are a powerful complement (not a substitute) for relational databases, while providing more choices. If a business is ready to migrate data, the important criteria for choosing NoSQL are the CAP (consistency, availability, and partition tolerance), which is what we call consistency, availability, and partitioning tolerance. But the CAP principle requires that only two of the consistency, availability, and partition tolerance can be selected in a distributed system. So if the enterprise thinks consistency is important then the relational database should be the preferred object.

For example, in applications such as banking, consistency is important, requiring that each block of data be considered at all times. The availability of the CAP principle cannot be ignored, and data availability in some areas is more important than waiting for all the transaction data to be collected. Finally, when scaling horizontally, partitioning tolerance is particularly critical to document databases. But MongoDB does not support complex transactions, only a small number of atomic operations, so it does not apply to "transfer" and other transactions and consistency requirements are very high. This requires a relational database to have a high level of control over the transaction.

(Responsible editor: The good of the Legacy)