Introduction to Azure Cosmos DB
Azure Cosmos DB is a globally distributed, multi-model database service from Microsoft Azure. It provides robust support for document, key-value, graph, and column-family data models, offering low latency and high availability to applications worldwide.
What is Azure Cosmos DB?
Azure Cosmos DB is designed to be a highly available, mission-critical, and globally scalable database. It's the first and only globally distributed database service that offers native support for multiple data models and APIs. This means you can use your existing application code and interact with Cosmos DB using APIs like:
- SQL (Core) API: A familiar document database API for JSON documents.
- MongoDB API: For applications built with MongoDB.
- Cassandra API: For applications built with Apache Cassandra.
- Gremlin API: For graph databases.
- Table API: For key-value and document data.
Key Features and Benefits
- Global Distribution: Easily distribute your data across any number of Azure regions worldwide. Replicate data where your users are to provide faster access.
- Guaranteed Throughput: Offers guaranteed low latency and high availability through its comprehensive service level agreements (SLAs).
- Elastic Scalability: Scale throughput and storage independently and elastically, on demand.
- Multi-Model Support: Access your data using various APIs, including SQL, MongoDB, Cassandra, Gremlin, and Table.
- Tunable Consistency: Choose from five well-defined consistency levels, from strong to eventual, to balance consistency and availability.
- Schema-Agnostic: Built for modern applications, it doesn't require schema management.
Core Concepts
Understanding these core concepts is crucial for working with Azure Cosmos DB:
- Accounts: The top-level resource in Azure Cosmos DB.
- Databases: A container for resources like containers and users.
- Containers: A schema-agnostic container of items (documents, key-value pairs, etc.) that serves as the basis of partitioning and scalability.
- Items: The entities stored within a container. In the SQL API, these are JSON documents.
- Partition Key: A property within an item that is used to determine which partition the item is stored in. This is critical for scalability and performance.
- Throughput: Measured in Request Units per second (RU/s), it represents the computational power required for your database operations.
Use Cases
Azure Cosmos DB is ideal for a wide range of applications, including:
- Web, mobile, gaming, and IoT applications that require low latency and global reach.
- Applications that need to handle unpredictable and rapid variations in traffic.
- Real-time big data analytics.
- Applications that require 99.999% availability.
In the following sections, you will learn how to get started with Azure Cosmos DB, explore its data modeling strategies, and understand how to leverage its various APIs for your specific needs.