Azure Cosmos DB is Microsoft’s proprietary globally-distributed, multi-model database service. It delivers turnkey global distribution, elastic scaling, and low latency. The core attribute that makes Azure Cosmos DB unique is that you can leverage multiple models and APIs to access and query your data. The following are the APIs that Azure Cosmos DB provides:
1. SQL API:
This API is a JSON-based, document-oriented API. If you’ve been using a standalone or on-premise SQL Server database and want to transition into a globally-distributed system, transitioning to Azure Cosmos DB through the SQL API would be a seamless experience. You will be able to use familiar SQL syntax for querying your documents.
2. MongoDB API:
It offers comprehensive support for MongoDB query language constructs, allowing developers to use familiar MongoDB client SDKs with Cosmos DB. This API is ideal for those applications that are already using MongoDB as their data layer because it doesn’t require any changes in source code.
3. Cassandra API:
Azure Cosmos DB provides this API as a service with APIs compatible with Apache Cassandra. This allows you to use existing Apache drivers, and any other software compatible with Cassandra, with your Azure Cosmos DB.
4. Azure Table API:
Azure Cosmos DB implements the Azure Table API for apps that need a key-value store with a schemaless design. Existing applications using Azure Table Storage can migrate to Azure Cosmos DB to take advantage of global distribution and automatic secondary indexes.
5. Gremlin API:
Designed for creating and managing graph databases. Graph databases use graph structures for semantic queries, making them perfect for managing hierarchical and interconnected data. For example, the Gremlin API is ideal for social network, geospatial, routing, and recommendation applications because these types of applications often deal with interconnected datasets.
API Comparison
| API | Capabilities |
|---|---|
| SQL API | Document databases using SQL syntax |
| MongoDB API | MongoDB-compatible database service |
| Cassandra API | Apache Cassandra-compatible database service |
| Azure Table API | Key-value store with schemaless design |
| Gremlin API | Create and manage graph databases |
All the APIs support key-value, document data types, column-family, and graph models for data. These APIs are fully supported by Azure Cosmos DB, offer native tooling, support, and customer care. Depending on your existing environment and programming language, you can choose any of these APIs within Azure Cosmos DB to for a seamless transition and progression.
Examples
Given an example for SQL API, where querying is as simple as using traditional SQL-syntax:
SELECT *
FROM Families f
WHERE f.id = “Andersen.1”
Under MongoDB API, you’d use MongoDB client SDKs:
var myCursor = db.families.find( { id: “Andersen.1” } );
For Cassandra API, you can use the familiar CQL (Cassandra Query Language):
SELECT * FROM families WHERE id = ‘Andersen.1’;
Remember, the choice of API doesn’t alter the underlying capabilities provided by the Azure Cosmos DB service, it merely changes the way you interact with your data.
Microsoft Azure Data Fundamentals (DP-900)
Microsoft Azure Data Fundamentals (DP-900) is an excellent course that helps in understanding different data platform technologies, concepts of relational and non-relational data, and different types of data workloads such as transactional or analytical. It also provides a deep understanding of each API and how to use them with Azure Cosmos DB.
Practice Test
True or False: Azure Cosmos DB provides five APIs: SQL API, MongoDB API, Cassandra API, Gremlin API, and Table API.
- True
- False
Answer: True
Explanation: Azure Cosmos DB does indeed provide these five APIs – SQL, MongoDB, Cassandra, Gremlin, and Table- for creating, querying, and managing resources.
Which API is Azure Cosmos DB’s SQL API built on?
- A) JavaScript
- B) Python
- C) C++
- D) Java
Answer: A) JavaScript
Explanation: Azure Cosmos DB’s SQL API is built on JavaScript, allowing it to support JavaScript’s type system, expressions, and functions.
True or False: Azure Cosmos DB’s MongoDB API allows developers to use MongoDB’s native drivers and tools to interact with their data.
- True
- False
Answer: True
Explanation: Azure Cosmos DB’s MongoDB API is designed to be fully compatible with the MongoDB wire protocol, allowing developers to use native MongoDB drivers and tools to interact with their MongoDB databases within Azure Cosmos DB.
Azure Cosmos DB’s Cassandra API enables developers to interact with their data using which query language?
- A) SparkQL
- B) SQL
- C) CQL
- D) BQL
Answer: C) CQL
Explanation: The Cassandra Query Language (CQL) is the native query language for Apache Cassandra, which Azure Cosmos DB’s Cassandra API allows developers to use to interact with their data.
What does the Gremlin API in Azure Cosmos DB enable?
- A) SQL-like query language
- B) MongoDB native drivers compatibility
- C) Graph traversal
- D) Tabular data read and write
Answer: C) Graph traversal
Explanation: The Gremlin API in Azure Cosmos DB is specifically meant for graph traversal, allowing developers to work with graph databases.
True or False: Azure Cosmos DB’s Table API provides automatic secondary indexes.
- True
- False
Answer: True
Explanation: Azure’s Cosmos DB’s Table API does indeed provide automatic secondary indexes, offering a high-performance key-value interface.
Which Azure Cosmos DB API supports JSON and JavaScript’s type system, expressions, and functions?
- A) MongoDB API
- B) SQL API
- C) Cassandra API
- D) Table API
Answer: B) SQL API
Explanation: The SQL API in Azure Cosmos DB supports JSON and JavaScript’s type system, expressions, and functions, enabling easy querying of hierarchical JSON data.
Which Azure Cosmos DB API is not wire protocol compatible with its source database?
- A) MongoDB API
- B) SQL API
- C) Cassandra API
- D) Gremlin API
Answer: B) SQL API
Explanation: The SQL API in Azure Cosmos DB is not wire protocol compatible with SQL Server. It uses a SQL-like language for queries, but it is not the same as SQL Server.
Which Azure Cosmos DB API is designed specifically for graph databases?
- A) SQL API
- B) MongoDB API
- C) Cassandra API
- D) Gremlin API
Answer: D) Gremlin API
Explanation: The Gremlin API in Azure Cosmos DB is designed specifically for graph databases. It allows for complex graph traversals for managing graph representations of data.
True or False: The Cassandra API in Azure Cosmos DB supports Cassandra’s native drivers and tools.
- True
- False
Answer: True
Explanation: Just like the MongoDB API, the Cassandra API in Azure Cosmos DB supports its source database’s native drivers and tools, allowing for seamless interaction with the data.
Interview Questions
1. What is Azure Cosmos DB?
Azure Cosmos DB is a globally distributed, multi-model database service designed to enable fast and extremely low-latency access to your data at any scale.
2. How many APIs does Azure Cosmos DB support?
Azure Cosmos DB supports five APIs: SQL API, MongoDB API, Cassandra API, Gremlin API, and Table API.
3. What is the SQL API in Azure Cosmos DB?
The SQL API allows you to use a SQL-like query language to interact with Azure Cosmos DB. It provides a JSON document data model that enables schema-agnostic data.
4. How does the MongoDB API in Azure Cosmos DB work?
The MongoDB API allows you to use existing MongoDB SDKs and tools to work with Azure Cosmos DB. This API provides compatibility with existing MongoDB applications.
5. What is the Cassandra API in Azure Cosmos DB?
The Cassandra API in Azure Cosmos DB is compatible with existing Apache Cassandra SDKs and tools, enabling you to interact with data using Cassandra query language (CQL) syntax.
6. How does the Gremlin API in Azure Cosmos DB facilitate graph data models?
The Gremlin API supports graph data models and allows you to use the Gremlin query language to interact with your data in a graph database on Azure Cosmos DB.
7. What is the purpose of the Table API in Azure Cosmos DB?
The Table API provides support for key-value data models and enables you to use Azure Cosmos DB as a key-value store, similar to Azure Table Storage.
8. How does Azure Cosmos DB ensure global distribution?
Azure Cosmos DB automatically replicates data to regions of your choice to provide low latency and high availability globally.
9. Can you switch between different APIs in Azure Cosmos DB for a single database?
Yes, you can switch between APIs on existing Azure Cosmos DB accounts to accommodate evolving application requirements.
10. Which API in Azure Cosmos DB is recommended for applications requiring a SQL-like query language?
The SQL API is recommended for applications that require a SQL-like query language and a schema-agnostic data model.
11. How does Azure Cosmos DB pricing vary based on API usage?
Pricing for Azure Cosmos DB is based on the data and throughput consumed by each API. Each API may have different pricing tiers and models.
12. Which API in Azure Cosmos DB is best suited for applications with graph data models?
The Gremlin API is the best choice for applications requiring a graph data model and usage of the Gremlin query language.
13. Can you use multiple APIs within the same Azure Cosmos DB account?
Yes, you can create multiple containers within an Azure Cosmos DB account, each utilizing a different API, based on the specific requirements of the application.
14. Why would an application developer choose the MongoDB API in Azure Cosmos DB over the SQL API?
An application developer may choose the MongoDB API for Azure Cosmos DB to leverage existing MongoDB skills, tools, and integrations while benefiting from the globally distributed nature of Azure Cosmos DB.
15. How does the Table API in Azure Cosmos DB differ from Azure Table Storage?
While the Table API in Azure Cosmos DB provides similar key-value store functionality as Azure Table Storage, it also offers the global distribution capabilities and scalability of Azure Cosmos DB.
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