Azure Cosmos DB Overview

What is Azure Cosmos DB?

Azure Cosmos DB is a globally distributed, multi-model database service from Microsoft Azure. It offers comprehensive SLAs on availability, latency, throughput, and consistency, providing robust support for various data models including document, key-value, graph, and column-family.

It's designed for mission-critical applications that require high availability, elastic scalability, and low-latency data access worldwide.

Key Features

Globally Distributed

Replicate your data across any number of Azure regions with active-active capabilities.

Elastic Scalability

Scale throughput and storage up or down on demand, independently per API.

Multi-Model Support

Support for multiple APIs including SQL (Core), MongoDB, Cassandra, Gremlin, and Table.

Guaranteed SLAs

Industry-leading Service Level Agreements for throughput, latency, availability, and consistency.

Enterprise Security

Robust security features including VNet integration, private endpoints, and role-based access control.

Low Latency

Single-digit millisecond latency for reads and writes at the 99th percentile.

Supported APIs

Cosmos DB offers a choice of APIs, allowing you to use the familiar query languages and SDKs:

SQL (Core API): The native and most powerful API, offering JSON document querying with rich indexing.
MongoDB API: Compatible with MongoDB wire protocol, allowing you to use existing MongoDB drivers and tools.
Cassandra API: Highly scalable, distributed database with a familiar CQL (Cassandra Query Language) interface.
Gremlin API: A graph database API for complex relationship traversals and graph computations.
Table API: For applications migrating from Azure Table Storage, providing a key-value store.

Common Use Cases

IoT Data: Ingesting and processing massive amounts of telemetry data from connected devices.
Web & Mobile Applications: Providing a highly available and scalable backend for user data.
Gaming: Storing player profiles, game state, and leaderboards with low latency.
E-commerce: Managing product catalogs, shopping carts, and order history.
Real-time Analytics: Powering dashboards and analytics with rapidly changing data.

Getting Started

Creating a Cosmos DB account is straightforward through the Azure portal, Azure CLI, or programmatically.

Example: Creating a SQL (Core) API Account (Azure CLI)

az cosmosdb create \
    --name mycosmosdbaccount \
    --resource-group myresourcegroup \
    --kind GlobalDocumentDB \
    --locations region=EastUS name=EastUS region=WestUS name=WestUS
            

Example: Inserting a Document (SQL API using JavaScript SDK)

// Initialize client

const { CosmosClient } = require("@azure/cosmos");

const endpoint = "YOUR_ENDPOINT";

const key = "YOUR_PRIMARY_KEY";

const client = new CosmosClient({ endpoint, key });

// Get container reference

const container = client.database("myDatabase").container("myContainer");

// Insert item

const newItem = { id: "item1", category: "personal", name: "groceries", description: "Monthly shopping" };

await container.items.create(newItem);

console.log("Item inserted successfully!");