Concepts

Azure Cosmos DB, a globally distributed, multi-model database service provided by Microsoft Azure, offers various application programming interfaces (APIs) to facilitate seamless integration with different programming languages and frameworks. These APIs allow developers to interact with Azure Cosmos DB using their preferred programming languages, enabling them to build scalable, high-performance, and globally distributed applications. In this article, we will explore the different APIs offered by Azure Cosmos DB and their relevance to the Microsoft Azure Data Fundamentals exam.

1. SQL API:

The SQL API is the default and most widely used API for Azure Cosmos DB. It provides developers with a SQL-like query language to perform CRUD (create, read, update, delete) operations on JSON documents stored in Azure Cosmos DB containers. The SQL API supports rich query capabilities, including filtering, sorting, aggregation, and joining multiple documents. Here’s an example of executing a SQL query using the .NET SDK:

// Using the SQL API with .NET SDK
using Microsoft.Azure.Cosmos;

// Instantiate a Cosmos DB client with the connection string
CosmosClient cosmosClient = new CosmosClient("connection-string");

// Get a reference to the database and container
Database database = cosmosClient.GetDatabase("database-id");
Container container = database.GetContainer("container-id");

// Execute a SQL query
QueryDefinition queryDefinition = new QueryDefinition("SELECT * FROM c WHERE c.Type = 'Product'");
FeedIterator feedIterator = container.GetItemQueryIterator(queryDefinition);

while (feedIterator.HasMoreResults)
{
FeedResponse response = await feedIterator.ReadNextAsync();
foreach (Product product in response)
{
Console.WriteLine($"{product.Id} - {product.Name}");
}
}

2. MongoDB API:

Azure Cosmos DB’s MongoDB API allows developers to use their existing MongoDB application code and skills to interact with Azure Cosmos DB seamlessly. It provides full compatibility with the MongoDB wire protocol, enabling easy migration of MongoDB applications to Azure Cosmos DB without changing the code. The MongoDB API supports features like CRUD operations, indexes, queries, and aggregation pipelines. Here’s an example of using the MongoDB API with Node.js:

// Using the MongoDB API with Node.js
const { MongoClient } = require('mongodb');

// Connect to the Azure Cosmos DB MongoDB API endpoint
const uri = 'mongodb://:@:10255/admin?ssl=true';

// Create a MongoClient instance
const client = new MongoClient(uri);

// Connect to the MongoDB API
await client.connect();

// Get a reference to the database and collection
const database = client.db('database-id');
const collection = database.collection('collection-id');

// Insert a document
const result = await collection.insertOne({ name: 'John Doe', age: 30 });
console.log(`Inserted document with _id: ${result.insertedId}`);

// Query documents
const documents = await collection.find({ age: { $gte: 25 } }).toArray();
console.log(documents);

// Disconnect from the database
await client.close();

3. Cassandra API:

The Cassandra API in Azure Cosmos DB allows developers to build applications using the Cassandra Query Language (CQL) and leverage the benefits of the Azure Cosmos DB’s global distribution, scalability, and low latency. This API is ideal for migrating existing Cassandra applications to Azure Cosmos DB without any code changes. It supports features such as tunable consistency levels, materialized views, and automatic indexing. Here’s an example of using the Cassandra API with Java:

// Using the Cassandra API with Java
import com.datastax.oss.driver.api.core.CqlSession;
import com.datastax.oss.driver.api.core.cql.ResultSet;

// Create a CqlSession instance
try (CqlSession session = CqlSession.builder()
.withCloudSecureConnectBundle("secure-connect-bundle.zip")
.withAuthCredentials("username", "password")
.build()) {

// Execute a CQL query
ResultSet rs = session.execute("SELECT * FROM keyspace.table WHERE id = 123");

// Process the result
rs.forEach(row -> System.out.println(row.getString("column1")));
}

4. Gremlin API:

The Gremlin API in Azure Cosmos DB provides support for graph-based data models using the Apache TinkerPop™ graph traversal language, Gremlin. It allows developers to model, query, and analyze complex, interconnected data with ease. The Gremlin API supports traversing graphs, creating vertices and edges, executing graph queries, and aggregating data. Here’s an example of using the Gremlin API with Python:

# Using the Gremlin API with Python
from azure.cosmosdb.gremlin import GremlinClient

# Create a GremlinClient instance
client = GremlinClient('wss://:443/', 'database-id', 'graph-id',
username='/dbs/database-id/colls/graph-id',
password='your-password')

# Execute a Gremlin query
query = 'g.V().has("name", "Alice").out("knows").values("name")'
result_set = client.submit(query)

# Process the result
for result in result_set:
print(result)

In conclusion, Azure Cosmos DB offers multiple APIs, including the SQL API, MongoDB API, Cassandra API, and Gremlin API, to cater to diverse application requirements and developer preferences. These APIs allow developers to seamlessly interact with Azure Cosmos DB using their preferred programming languages and frameworks, providing flexibility and ease of integration. Understanding these APIs is essential for the Microsoft Azure Data Fundamentals exam and will enable you to leverage Azure Cosmos DB’s capabilities effectively in your application development endeavors.

Answer the Questions in Comment Section

Select the correct statement about Azure Cosmos DB APIs:

  • a) Azure Cosmos DB supports only SQL API for data access.
  • b) Azure Cosmos DB supports multiple APIs, including SQL, Gremlin, Table, Cassandra, and MongoDB.
  • c) Azure Cosmos DB supports only Gremlin API for data access.
  • d) Azure Cosmos DB supports only MongoDB API for data access.

Correct answer: b) Azure Cosmos DB supports multiple APIs, including SQL, Gremlin, Table, Cassandra, and MongoDB.

True or False: The SQL API in Azure Cosmos DB provides a schema-less data model.

Correct answer: True

Select the correct statement about the Gremlin API in Azure Cosmos DB:

  • a) The Gremlin API is mainly used for querying relational data models.
  • b) The Gremlin API is specifically designed for working with graph databases.
  • c) The Gremlin API is used for storing and retrieving key-value pairs.
  • d) The Gremlin API is used for developing mobile applications.

Correct answer: b) The Gremlin API is specifically designed for working with graph databases.

True or False: The Table API in Azure Cosmos DB is suited for storing structured, JSON-like documents.

Correct answer: False

Select the correct statement about the Cassandra API in Azure Cosmos DB:

  • a) The Cassandra API supports a flexible schema.
  • b) The Cassandra API supports only SQL-based queries.
  • c) The Cassandra API is used for real-time stream processing.
  • d) The Cassandra API supports only key-value data models.

Correct answer: a) The Cassandra API supports a flexible schema.

True or False: The MongoDB API in Azure Cosmos DB provides a NoSQL document database service.

Correct answer: True

Select the correct statement about migrating data to Azure Cosmos DB:

  • a) Data can be migrated from any source to Azure Cosmos DB without any limitations.
  • b) Migrating data from the SQL API to other APIs is a seamless process.
  • c) Azure Cosmos DB provides built-in tools for automatic data migration.
  • d) Migrating data to Azure Cosmos DB requires manual scripting or custom tools.

Correct answer: d) Migrating data to Azure Cosmos DB requires manual scripting or custom tools.

True or False: Azure Cosmos DB provides automatic indexing for all APIs.

Correct answer: True

Select the correct statement about consistency levels in Azure Cosmos DB:

  • a) Consistency levels in Azure Cosmos DB are only applicable to the MongoDB API.
  • b) Consistency levels in Azure Cosmos DB determine the trade-off between data consistency and availability.
  • c) Azure Cosmos DB does not provide support for defining consistency levels.
  • d) Consistency levels in Azure Cosmos DB are fixed and cannot be customized.

Correct answer: b) Consistency levels in Azure Cosmos DB determine the trade-off between data consistency and availability.

True or False: Azure Cosmos DB supports multi-master replication across multiple Azure regions.

Correct answer: True

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Nada Riviere
9 months ago

Great overview of Azure Cosmos DB APIs! Helped me a lot for my DP-900 exam.

Regillio De Waardt
1 year ago

I found this post really helpful. Azure Cosmos DB has four APIs: SQL API, MongoDB API, Cassandra API, and Gremlin API. Understanding these is crucial for the exam.

Iina Wirkkala
1 year ago

Thanks for breaking down the APIs. Which API would you recommend for a newbie developer?

Gabrielle Dufour
1 year ago

Could someone explain the major use cases for each API in Azure Cosmos DB?

Claire Barrett
1 year ago

Appreciate the detailed information!

Neil Ferguson
4 months ago

I am preparing for DP-900 and this is exactly what I needed. Thanks!

Saana Lampinen
1 year ago

Great post! But what are the differences in performance among these APIs?

Aarnoud De Backer
7 months ago

I think the MongoDB API is quite versatile, especially for developers familiar with MongoDB.

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