Documentdb 简明教程

DocumentDB - Advantages

DocumentDB 脱颖而出，具有非常独特的功能。Azure DocumentDB 提供了以下关键功能和优势。

DocumentDB stands out with some very unique capabilities. Azure DocumentDB offers the following key capabilities and benefits.

Schema Free

在关系数据库中，每个表都具有一个架构，用于定义每个表中的每行必须遵循的列和数据类型。

In a relational database, every table has a schema that defines the columns and data types that each row in the table must conform to.

相反，文档数据库没有定义架构，并且每个文档的结构可以不同。

In contrast, a document database has no defined schema, and every document can be structured differently.

SQL Syntax

DocumentDB 能够使用 SQL 语言进行复杂的临时查询，并且每份文档在创建后都可以立即进行查询。您可以在文档层次结构中的任何位置对任何属性进行搜索。

DocumentDB enables complex ad-hoc queries using SQL language, and every document is instantly queryable the moment it’s created. You can search on any property anywhere within the document hierarchy.

Tunable Consistency

它提供了一些详细且定义良好的一致性级别，这使您能够在一致性、可用性和延迟之间进行合理的权衡。

It provides some granular, well-defined consistency levels, which allows you to make sound trade-offs between consistency, availability, and latency.

您可以从四个定义明确的一致性级别中进行选择，以在一致性和性能之间实现最佳权衡。对于查询和读取操作，DocumentDB 提供四个不同的级别 −

You can select from four well-defined consistency levels to achieve optimal trade-off between consistency and performance. For queries and read operations, DocumentDB offers four distinct consistency levels −

  1. Strong

  2. Bounded-staleness

  3. Session

  4. Eventual

Elastic Scale

可伸缩性是 NoSQL 的关键，而 DocumentDB 则提供了此功能。DocumentDB 已经证明了它的可伸缩性。

Scalability is the name of the game with NoSQL, and DocumentDB delivers. DocumentDB has already been proven its scale.

  1. Major services like Office OneNote and Xbox are already backed by DocumentDB with databases containing tens of terabytes of JSON documents, over a million active users, and operating consistently with 99.95% availability.

  2. You can elastically scale DocumentDB with predictable performance by creating more units as your application grows.

Fully Managed

DocumentDB 以在 Azure 上运行的服务形式提供，作为一个完全管理的基于云的平台。

DocumentDB is available as a fully managed cloud-based platform as a service running on Azure.

  1. There is simply nothing for you to install or manage.

  2. There are no servers, cables, no operating systems or updates to deal with, no replicas to set up.

  3. Microsoft does all that work and keeps the service running.

  4. Within literally minutes, you can get started working with DocumentDB using just a browser and an Azure subscription.