Help Center/ Document Database Service/ Service Overview/ What Is DDS?
Updated on 2022-12-14 GMT+08:00
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What Is DDS?

Document Database Service (DDS), compatible with MongoDB, is a secure, high availability (HA) database service that is reliable, scalable, and easy to use. It provides functions such as one-click deployment, elastic capacity expansion, disaster recovery, backup, restoration, monitoring, and alarm reporting.

Before using DDS, you need to be familiar with MongoDB and the MongoDB protocol. For details, see official documents.

Storage Structure

Figure 1 Storage structure

The basic management unit of DDS is an instance. A DDS instance consists of database, collection, and document.

DDS is fully compatible with the MongoDB protocol, so some terms, data structures, and basic syntax of DDS are the same as those of MongoDB. The following table lists the difference between common terms in MongoDB and relational databases to help you better understand and use DDS.

Table 1 Terms

MongoDB

Description

Relational Database

Database

A DDS instance contains multiple databases, and a database contains multiple collections.

Database

Collection

A collection is a group of MongoDB documents.

Table

Document

A document is a group of key-value pairs (BSONs) and is the most basic unit in MongoDB.

Row

Data Structure

MongoDB uses JSON-like documents when storing documents in collections. The following figure compares data structures between relational databases and MongoDB, helping you have a better understanding of MongoDB concepts.

Figure 2 Data structures

Why DDS?

For details, see Advantages and Typical Application Scenarios.

Product Pricing

For details, see Pricing Details.

Compatible DB Engines and Versions

For details about the compatible DB engines and versions, see DB Engines and Versions.

Deployment Suggestions

Before deploying DDS, consider the following factors:

  • Region and Availability Zone: You should select a region and AZs based on the geographical locations of your users, product prices, DR capabilities, and network latency. Once DB instances are successfully created in specific AZs in a region, the region cannot be changed. For more information, see Region and AZ.
  • Network planning: When creating a DDS DB instance, you are advised to use the Virtual Private Network (VPC) and subnet where the Elastic Cloud Server (ECS) is deployed.
  • Data security: DDS provides comprehensive assurance for data security. You can deploy DB instances in multiple AZs and use audit logs, isolated networks, security groups, and data encryption to ensure data security.