Azure Cosmos DB is a fully managed NoSQL database service that provides global distribution, elastic scaling, and multi-model support with comprehensive SLAs for throughput, latency, availability, and consistency. It offers multiple APIs including SQL (Core), MongoDB, Cassandra, Gremlin, and Table, making it highly versatile for various application patterns.
Microsoft.Azure.CosmosMicrosoft.Azure.Cosmos SDKAzure.Data.Tables for Azure Table StorageMicrosoft.Azure.Cosmos.Table (discontinued)<!-- For SQL API (Recommended) -->
<PackageReference Include="Microsoft.Azure.Cosmos" Version="3.37.0" />
<!-- For MongoDB API -->
<PackageReference Include="MongoDB.Driver" Version="2.22.0" />
<!-- For Table API (if not using unified Cosmos SDK) -->
<PackageReference Include="Azure.Data.Tables" Version="12.8.0" /><!-- DEPRECATED: Legacy SQL API SDK -->
<!-- <PackageReference Include="Microsoft.Azure.DocumentDB" Version="2.x.x" /> -->
<!-- DEPRECATED: Legacy Table API SDK -->
<!-- <PackageReference Include="Microsoft.Azure.Cosmos.Table" Version="1.x.x" /> -->
<!-- DEPRECATED: Original Table Storage SDK -->
<!-- <PackageReference Include="WindowsAzure.Storage" Version="9.x.x" /> --><!-- For dependency injection -->
<PackageReference Include="Microsoft.Extensions.DependencyInjection" Version="7.0.0" />
<PackageReference Include="Microsoft.Extensions.Configuration" Version="7.0.0" />
<!-- For managed identity authentication -->
<PackageReference Include="Azure.Identity" Version="1.10.4" />The CosmosClient class is the primary interface for interacting with Azure Cosmos DB SQL API. It provides a thread-safe client that manages connections, handles retries, and implements the Azure Cosmos DB protocol.
using Microsoft.Azure.Cosmos;
// Connection using endpoint and key (basic example)
var endpoint = "https://your-account.documents.azure.com:443/";
var key = "your-primary-key";
var cosmosClient = new CosmosClient(endpoint, key, new CosmosClientOptions
{
ConnectionMode = ConnectionMode.Direct,
SerializerOptions = new CosmosSerializationOptions
{
PropertyNamingPolicy = CosmosPropertyNamingPolicy.CamelCase
}
});The CosmosClient behavior can be customized with CosmosClientOptions:
var clientOptions = new CosmosClientOptions
{
// Performance options
ConnectionMode = ConnectionMode.Direct, // Direct for better performance
ApplicationName = "YourApplication",
// Consistency level
ConsistencyLevel = ConsistencyLevel.Session, // Default
// Regional preferences
ApplicationRegion = "West US 2",
// Serialization
SerializerOptions = new CosmosSerializationOptions
{
PropertyNamingPolicy = CosmosPropertyNamingPolicy.CamelCase,
IgnoreNullValues = true
},
// Resilience
MaxRetryAttemptsOnRateLimitedRequests = 9,
MaxRetryWaitTimeOnRateLimitedRequests = TimeSpan.FromSeconds(30)
};
var cosmosClient = new CosmosClient(endpoint, key, clientOptions);// Create or get a database
Database database = await cosmosClient.CreateDatabaseIfNotExistsAsync("MyDatabase");
// Create container with RU/s provisioning and partition key
ContainerProperties containerProperties = new ContainerProperties
{
Id = "MyContainer",
PartitionKeyPath = "/partitionKey",
// Optional: configure indexing policy
IndexingPolicy = new IndexingPolicy
{
Automatic = true,
IndexingMode = IndexingMode.Consistent,
IncludedPaths = { new IncludedPath { Path = "/*" } },
ExcludedPaths = { new ExcludedPath { Path = "/path/to/exclude/*" } }
}
};
// Create with 400 RU/s throughput
Container container = await database.CreateContainerIfNotExistsAsync(
containerProperties,
ThroughputProperties.CreateManualThroughput(400));In Azure Cosmos DB’s SQL API, you work with “items” - JSON documents with unique IDs:
// Define a model class
public class TodoItem
{
[JsonProperty("id")]
public string Id { get; set; } = Guid.NewGuid().ToString();
[JsonProperty("partitionKey")]
public string PartitionKey { get; set; }
public string Title { get; set; }
public bool Completed { get; set; }
public DateTime CreatedDate { get; set; } = DateTime.UtcNow;
}
// Alternative: Using System.Text.Json attributes
public class TodoItemWithSystemTextJson
{
[JsonPropertyName("id")]
public string Id { get; set; } = Guid.NewGuid().ToString();
[JsonPropertyName("partitionKey")]
public string PartitionKey { get; set; }
public string Title { get; set; }
public bool Completed { get; set; }
public DateTime CreatedDate { get; set; } = DateTime.UtcNow;
}CosmosDB SQL API provides a rich SQL-like query language for JSON documents. You can query using strongly-typed entities, dynamic objects, or raw JSON responses:
// 1. Point read by ID and partition key (most efficient)
try
{
ItemResponse<TodoItem> response = await container.ReadItemAsync<TodoItem>(
id: "task-1",
partitionKey: new PartitionKey("personal"));
TodoItem item = response.Resource;
Console.WriteLine($"Retrieved item: {item.Title}, RUs consumed: {response.RequestCharge}");
}
catch (CosmosException ex) when (ex.StatusCode == HttpStatusCode.NotFound)
{
Console.WriteLine("Item not found");
}
// 2. SQL Query
QueryDefinition query = new QueryDefinition(
"SELECT * FROM c WHERE c.partitionKey = @partitionKey AND c.completed = @status")
.WithParameter("@partitionKey", "personal")
.WithParameter("@status", false);
FeedIterator<TodoItem> resultSet = container.GetItemQueryIterator<TodoItem>(
query,
requestOptions: new QueryRequestOptions
{
MaxItemCount = 10,
PartitionKey = new PartitionKey("personal")
});
double totalRequestCharge = 0;
List<TodoItem> results = new List<TodoItem>();
while (resultSet.HasMoreResults)
{
FeedResponse<TodoItem> response = await resultSet.ReadNextAsync();
totalRequestCharge += response.RequestCharge;
results.AddRange(response.ToList());
}
Console.WriteLine($"Found {results.Count} items, total RU consumed: {totalRequestCharge}");
// 3. LINQ query
using Microsoft.Azure.Cosmos.Linq;
IOrderedQueryable<TodoItem> linqQueryable = container.GetItemLinqQueryable<TodoItem>();
var query = linqQueryable
.Where(t => t.PartitionKey == "personal" && !t.Completed)
.OrderBy(t => t.CreatedDate);
using FeedIterator<TodoItem> linqResultSet = query.ToFeedIterator();
while (linqResultSet.HasMoreResults)
{
foreach (var item in await linqResultSet.ReadNextAsync())
{
Console.WriteLine($"{item.Title}: {item.CreatedDate}");
}
}You can work with dynamic objects when you don’t want to define strongly-typed classes:
// 1. Point read with dynamic object
ItemResponse<dynamic> dynamicResponse = await container.ReadItemAsync<dynamic>(
id: "task-1",
partitionKey: new PartitionKey("personal"));
dynamic item = dynamicResponse.Resource;
Console.WriteLine($"Title: {item.title}, Completed: {item.completed}");
// 2. Query with dynamic objects
QueryDefinition dynamicQuery = new QueryDefinition(
"SELECT * FROM c WHERE c.partitionKey = @partitionKey")
.WithParameter("@partitionKey", "personal");
FeedIterator<dynamic> dynamicResultSet = container.GetItemQueryIterator<dynamic>(
dynamicQuery,
requestOptions: new QueryRequestOptions
{
PartitionKey = new PartitionKey("personal")
});
while (dynamicResultSet.HasMoreResults)
{
FeedResponse<dynamic> response = await dynamicResultSet.ReadNextAsync();
foreach (dynamic item in response)
{
Console.WriteLine($"ID: {item.id}, Title: {item.title}");
}
}
// 3. Creating items with dynamic objects
dynamic newDynamicItem = new
{
id = "dynamic-task-1",
partitionKey = "personal",
title = "Task created with dynamic object",
completed = false,
tags = new[] { "dynamic", "example" }
};
await container.CreateItemAsync<dynamic>(
newDynamicItem,
new PartitionKey("personal"));For maximum flexibility, you can work directly with JSON strings:
// 1. Query returning raw JSON stream
QueryDefinition jsonQuery = new QueryDefinition(
"SELECT * FROM c WHERE c.partitionKey = @partitionKey")
.WithParameter("@partitionKey", "personal");
FeedIterator jsonIterator = container.GetItemQueryStreamIterator(
jsonQuery,
requestOptions: new QueryRequestOptions
{
PartitionKey = new PartitionKey("personal")
});
while (jsonIterator.HasMoreResults)
{
using ResponseMessage response = await jsonIterator.ReadNextAsync();
if (response.IsSuccessStatusCode)
{
using StreamReader reader = new StreamReader(response.Content);
string jsonContent = await reader.ReadToEndAsync();
Console.WriteLine($"Raw JSON Response: {jsonContent}");
// Parse manually if needed
using JsonDocument document = JsonDocument.Parse(jsonContent);
JsonElement root = document.RootElement;
if (root.TryGetProperty("Documents", out JsonElement documents))
{
foreach (JsonElement item in documents.EnumerateArray())
{
if (item.TryGetProperty("title", out JsonElement title))
{
Console.WriteLine($"Title from JSON: {title.GetString()}");
}
}
}
}
}
// 2. Point read with raw JSON
using ResponseMessage jsonResponse = await container.ReadItemStreamAsync(
"task-1",
new PartitionKey("personal"));
if (jsonResponse.IsSuccessStatusCode)
{
using StreamReader reader = new StreamReader(jsonResponse.Content);
string itemJson = await reader.ReadToEndAsync();
Console.WriteLine($"Raw JSON Item: {itemJson}");
}
// 3. Create item with raw JSON
string newItemJson = """
{
"id": "json-task-1",
"partitionKey": "personal",
"title": "Task created with raw JSON",
"completed": false,
"metadata": {
"createdBy": "system",
"priority": "high"
}
}
""";
using MemoryStream stream = new MemoryStream(Encoding.UTF8.GetBytes(newItemJson));
using ResponseMessage createResponse = await container.CreateItemStreamAsync(
stream,
new PartitionKey("personal"));
if (createResponse.IsSuccessStatusCode)
{
Console.WriteLine($"Created item with status: {createResponse.StatusCode}");
}Different approaches have different performance characteristics:
// Performance comparison example
var stopwatch = Stopwatch.StartNew();
// 1. Strongly-typed (fastest deserialization)
var typedResults = new List<TodoItem>();
var typedIterator = container.GetItemQueryIterator<TodoItem>(
new QueryDefinition("SELECT * FROM c WHERE c.partitionKey = 'personal'"),
requestOptions: new QueryRequestOptions { PartitionKey = new PartitionKey("personal") });
while (typedIterator.HasMoreResults)
{
typedResults.AddRange(await typedIterator.ReadNextAsync());
}
stopwatch.Stop();
Console.WriteLine($"Strongly-typed query: {stopwatch.ElapsedMilliseconds}ms");
stopwatch.Restart();
// 2. Dynamic objects (flexible but slower)
var dynamicResults = new List<dynamic>();
var dynamicIterator = container.GetItemQueryIterator<dynamic>(
new QueryDefinition("SELECT * FROM c WHERE c.partitionKey = 'personal'"),
requestOptions: new QueryRequestOptions { PartitionKey = new PartitionKey("personal") });
while (dynamicIterator.HasMoreResults)
{
dynamicResults.AddRange(await dynamicIterator.ReadNextAsync());
}
stopwatch.Stop();
Console.WriteLine($"Dynamic query: {stopwatch.ElapsedMilliseconds}ms");
stopwatch.Restart();
// 3. Raw JSON (fastest network transfer, manual parsing required)
var jsonIterator = container.GetItemQueryStreamIterator(
new QueryDefinition("SELECT * FROM c WHERE c.partitionKey = 'personal'"),
requestOptions: new QueryRequestOptions { PartitionKey = new PartitionKey("personal") });
while (jsonIterator.HasMoreResults)
{
using var response = await jsonIterator.ReadNextAsync();
using var reader = new StreamReader(response.Content);
string json = await reader.ReadToEndAsync();
// Process JSON as needed
}
stopwatch.Stop();
Console.WriteLine($"Raw JSON query: {stopwatch.ElapsedMilliseconds}ms");SELECT VALUE c.name) to return only needed properties// Query with continuation token (pagination)
QueryDefinition largeQuery = new QueryDefinition("SELECT * FROM c");
QueryRequestOptions options = new QueryRequestOptions
{
MaxItemCount = 10
};
FeedIterator<TodoItem> iterator = container.GetItemQueryIterator<TodoItem>(
largeQuery,
requestOptions: options);
string continuationToken = null;
// First page
FeedResponse<TodoItem> page = await iterator.ReadNextAsync();
continuationToken = page.ContinuationToken;
ProcessItems(page);
// Later, get the next page using the continuation token
options.RequestContinuation = continuationToken;
iterator = container.GetItemQueryIterator<TodoItem>(largeQuery, requestOptions: options);You can create items using strongly-typed entities, dynamic objects, or raw JSON:
// Create a new item with strongly-typed class
var newItem = new TodoItem
{
Id = "task-1",
PartitionKey = "personal",
Title = "Complete Azure Cosmos DB documentation",
Completed = false
};
// Insert the item
try
{
ItemResponse<TodoItem> response = await container.CreateItemAsync(
newItem,
new PartitionKey(newItem.PartitionKey));
Console.WriteLine($"Created item: {newItem.Id}");
Console.WriteLine($"Request charge: {response.RequestCharge} RUs");
}
catch (CosmosException ex) when (ex.StatusCode == HttpStatusCode.Conflict)
{
Console.WriteLine("Item already exists");
}
// Upsert - create if not exists, replace if exists
await container.UpsertItemAsync(
newItem,
new PartitionKey(newItem.PartitionKey));
// Create with custom options
ItemRequestOptions requestOptions = new ItemRequestOptions
{
EnableContentResponseOnWrite = false, // Saves RUs by not returning the created item
ConsistencyLevel = ConsistencyLevel.Session
};
await container.CreateItemAsync(
newItem,
new PartitionKey(newItem.PartitionKey),
requestOptions);// Create with anonymous object
dynamic dynamicItem = new
{
id = "dynamic-task-2",
partitionKey = "personal",
title = "Task created with dynamic object",
completed = false,
priority = "high",
tags = new[] { "dynamic", "flexible" },
metadata = new
{
createdBy = "system",
version = "1.0"
}
};
ItemResponse<dynamic> dynamicResponse = await container.CreateItemAsync<dynamic>(
dynamicItem,
new PartitionKey("personal"));
Console.WriteLine($"Created dynamic item: {dynamicResponse.Resource.id}");
// Create with ExpandoObject for runtime flexibility
dynamic expandoItem = new ExpandoObject();
expandoItem.id = "expando-task-1";
expandoItem.partitionKey = "personal";
expandoItem.title = "Task created with ExpandoObject";
expandoItem.completed = false;
// Add properties dynamically
((IDictionary<string, object>)expandoItem)["customField"] = "customValue";
((IDictionary<string, object>)expandoItem)["timestamp"] = DateTime.UtcNow;
await container.CreateItemAsync<dynamic>(
expandoItem,
new PartitionKey("personal"));
// Upsert with dynamic objects
await container.UpsertItemAsync<dynamic>(
dynamicItem,
new PartitionKey("personal"));// Create item with JSON string
string newItemJson = """
{
"id": "json-task-2",
"partitionKey": "personal",
"title": "Task created with raw JSON",
"completed": false,
"priority": "medium",
"tags": ["json", "manual"],
"metadata": {
"createdBy": "api",
"source": "external-system",
"timestamp": "2025-01-15T10:30:00Z"
},
"customProperties": {
"nested": {
"value": 42,
"active": true
}
}
}
""";
// Create using stream for maximum performance
using MemoryStream stream = new MemoryStream(Encoding.UTF8.GetBytes(newItemJson));
using ResponseMessage createResponse = await container.CreateItemStreamAsync(
stream,
new PartitionKey("personal"));
if (createResponse.IsSuccessStatusCode)
{
Console.WriteLine($"Created JSON item with status: {createResponse.StatusCode}");
Console.WriteLine($"Request charge: {createResponse.Headers.RequestCharge} RUs");
// Read the created item from response if needed
using StreamReader reader = new StreamReader(createResponse.Content);
string createdItemJson = await reader.ReadToEndAsync();
Console.WriteLine($"Created item: {createdItemJson}");
}
else
{
Console.WriteLine($"Failed to create item: {createResponse.StatusCode}");
using StreamReader errorReader = new StreamReader(createResponse.Content);
string errorMessage = await errorReader.ReadToEndAsync();
Console.WriteLine($"Error: {errorMessage}");
}
// Upsert with JSON stream
using MemoryStream upsertStream = new MemoryStream(Encoding.UTF8.GetBytes(newItemJson));
using ResponseMessage upsertResponse = await container.UpsertItemStreamAsync(
upsertStream,
new PartitionKey("personal"));
// Create with custom request options using JSON
ItemRequestOptions jsonRequestOptions = new ItemRequestOptions
{
EnableContentResponseOnWrite = false
};
using MemoryStream customStream = new MemoryStream(Encoding.UTF8.GetBytes(newItemJson));
using ResponseMessage customResponse = await container.CreateItemStreamAsync(
customStream,
new PartitionKey("personal"),
jsonRequestOptions);var stopwatch = Stopwatch.StartNew();
// 1. Strongly-typed (good balance of performance and type safety)
var typedItem = new TodoItem { Id = "perf-typed", PartitionKey = "test", Title = "Typed" };
await container.CreateItemAsync(typedItem, new PartitionKey("test"));
stopwatch.Stop();
Console.WriteLine($"Strongly-typed create: {stopwatch.ElapsedMilliseconds}ms");
stopwatch.Restart();
// 2. Dynamic object (flexible but slower serialization)
dynamic dynamicItem = new { id = "perf-dynamic", partitionKey = "test", title = "Dynamic" };
await container.CreateItemAsync<dynamic>(dynamicItem, new PartitionKey("test"));
stopwatch.Stop();
Console.WriteLine($"Dynamic create: {stopwatch.ElapsedMilliseconds}ms");
stopwatch.Restart();
// 3. Raw JSON (fastest, no serialization overhead)
string jsonItem = """{"id": "perf-json", "partitionKey": "test", "title": "JSON"}""";
using var stream = new MemoryStream(Encoding.UTF8.GetBytes(jsonItem));
await container.CreateItemStreamAsync(stream, new PartitionKey("test"));
stopwatch.Stop();
Console.WriteLine($"Raw JSON create: {stopwatch.ElapsedMilliseconds}ms");You can update items using strongly-typed entities, dynamic objects, or raw JSON through replace operations or patch operations:
// Read first, then update
try
{
// Get the existing item
ItemResponse<TodoItem> response = await container.ReadItemAsync<TodoItem>(
"task-1",
new PartitionKey("personal"));
TodoItem item = response.Resource;
// Modify properties
item.Title = "Updated title";
item.Completed = true;
// Update with optimistic concurrency control using ETag
ItemRequestOptions options = new ItemRequestOptions
{
IfMatchEtag = response.ETag
};
// Replace the item
await container.ReplaceItemAsync(
item,
item.Id,
new PartitionKey(item.PartitionKey),
options);
Console.WriteLine("Item updated successfully");
}
catch (CosmosException ex) when (ex.StatusCode == HttpStatusCode.PreconditionFailed)
{
Console.WriteLine("Item was modified by another process");
}
catch (CosmosException ex) when (ex.StatusCode == HttpStatusCode.NotFound)
{
Console.WriteLine("Item not found");
}
// Direct patch operations without reading first
PatchItemRequestOptions patchOptions = new PatchItemRequestOptions();
List<PatchOperation> patchOperations = new List<PatchOperation>
{
PatchOperation.Replace("/title", "New patched title"),
PatchOperation.Replace("/completed", true),
PatchOperation.Add("/tags", new[] { "important", "documentation" })
};
await container.PatchItemAsync<TodoItem>(
"task-1",
new PartitionKey("personal"),
patchOperations,
patchOptions);// Read and update with dynamic objects
ItemResponse<dynamic> dynamicResponse = await container.ReadItemAsync<dynamic>(
"dynamic-task-1",
new PartitionKey("personal"));
dynamic item = dynamicResponse.Resource;
// Modify properties
item.title = "Updated dynamic title";
item.completed = true;
item.lastModified = DateTime.UtcNow;
// Add new properties dynamically
item.updatedBy = "system";
item.version = "2.0";
// Replace with dynamic object
await container.ReplaceItemAsync<dynamic>(
item,
(string)item.id,
new PartitionKey((string)item.partitionKey));
// Patch operations with dynamic values
List<PatchOperation> dynamicPatchOps = new List<PatchOperation>
{
PatchOperation.Replace("/title", "Patched dynamic title"),
PatchOperation.Add("/metadata/lastUpdated", DateTime.UtcNow.ToString("O")),
PatchOperation.Replace("/priority", "urgent"),
PatchOperation.Remove("/tags/0") // Remove first tag
};
await container.PatchItemAsync<dynamic>(
"dynamic-task-1",
new PartitionKey("personal"),
dynamicPatchOps);
// Create or update with ExpandoObject
dynamic expandoUpdate = new ExpandoObject();
var expandoDict = (IDictionary<string, object>)expandoUpdate;
expandoDict["id"] = "expando-task-1";
expandoDict["partitionKey"] = "personal";
expandoDict["title"] = "Updated ExpandoObject";
expandoDict["completed"] = true;
expandoDict["updatedAt"] = DateTime.UtcNow;
// Add nested objects
expandoDict["metadata"] = new Dictionary<string, object>
{
["lastModifiedBy"] = "api",
["version"] = 2,
["changes"] = new[] { "title", "status" }
};
await container.UpsertItemAsync<dynamic>(
expandoUpdate,
new PartitionKey("personal"));// Replace using JSON stream
string updatedItemJson = """
{
"id": "json-task-1",
"partitionKey": "personal",
"title": "Updated JSON task",
"completed": true,
"priority": "high",
"tags": ["json", "updated"],
"metadata": {
"lastModified": "2025-01-15T15:30:00Z",
"modifiedBy": "api-service",
"version": 2
},
"history": [
{
"action": "created",
"timestamp": "2025-01-15T10:30:00Z"
},
{
"action": "updated",
"timestamp": "2025-01-15T15:30:00Z",
"changes": ["title", "completed", "priority"]
}
]
}
""";
// Replace with JSON stream
using MemoryStream replaceStream = new MemoryStream(Encoding.UTF8.GetBytes(updatedItemJson));
using ResponseMessage replaceResponse = await container.ReplaceItemStreamAsync(
replaceStream,
"json-task-1",
new PartitionKey("personal"));
if (replaceResponse.IsSuccessStatusCode)
{
Console.WriteLine($"Updated JSON item with status: {replaceResponse.StatusCode}");
Console.WriteLine($"Request charge: {replaceResponse.Headers.RequestCharge} RUs");
}
// Upsert with JSON stream (create if not exists, replace if exists)
using MemoryStream upsertStream = new MemoryStream(Encoding.UTF8.GetBytes(updatedItemJson));
using ResponseMessage upsertResponse = await container.UpsertItemStreamAsync(
upsertStream,
new PartitionKey("personal"));
// Optimistic concurrency with ETag using JSON
ItemRequestOptions etagOptions = new ItemRequestOptions
{
IfMatchEtag = "\"some-etag-value\"" // Get this from a previous read operation
};
using MemoryStream concurrencyStream = new MemoryStream(Encoding.UTF8.GetBytes(updatedItemJson));
try
{
using ResponseMessage concurrencyResponse = await container.ReplaceItemStreamAsync(
concurrencyStream,
"json-task-1",
new PartitionKey("personal"),
etagOptions);
}
catch (CosmosException ex) when (ex.StatusCode == HttpStatusCode.PreconditionFailed)
{
Console.WriteLine("Item was modified by another process - ETag mismatch");
}// Complex patch operations with different data types
List<PatchOperation> advancedPatchOps = new List<PatchOperation>
{
// Replace operations
PatchOperation.Replace("/title", "Advanced patched title"),
PatchOperation.Replace("/completed", true),
PatchOperation.Replace("/priority", "critical"),
// Add operations
PatchOperation.Add("/tags/-", "new-tag"), // Add to end of array
PatchOperation.Add("/metadata/patchedAt", DateTime.UtcNow),
PatchOperation.Add("/assignee", new { name = "John Doe", id = "user123" }),
// Remove operations
PatchOperation.Remove("/oldProperty"),
PatchOperation.Remove("/tags/0"), // Remove first element from array
// Increment operation (for numeric values)
PatchOperation.Increment("/retryCount", 1),
// Set operation (like replace, but creates the path if it doesn't exist)
PatchOperation.Set("/status/lastChecked", DateTime.UtcNow)
};
// Apply patch with conditional predicate
PatchItemRequestOptions advancedPatchOptions = new PatchItemRequestOptions
{
FilterPredicate = "FROM c WHERE c.version < 5" // Only apply if version is less than 5
};
try
{
ItemResponse<dynamic> patchResponse = await container.PatchItemAsync<dynamic>(
"task-1",
new PartitionKey("personal"),
advancedPatchOps,
advancedPatchOptions);
Console.WriteLine($"Patch applied successfully. New version: {patchResponse.Resource.version}");
}
catch (CosmosException ex) when (ex.StatusCode == HttpStatusCode.PreconditionFailed)
{
Console.WriteLine("Patch condition not met - item version is >= 5");
}var stopwatch = Stopwatch.StartNew();
// 1. Full replace with strongly-typed (type-safe but requires full object)
var typedItem = await container.ReadItemAsync<TodoItem>("perf-typed", new PartitionKey("test"));
typedItem.Resource.Title = "Updated";
await container.ReplaceItemAsync(typedItem.Resource, "perf-typed", new PartitionKey("test"));
stopwatch.Stop();
Console.WriteLine($"Strongly-typed replace: {stopwatch.ElapsedMilliseconds}ms");
stopwatch.Restart();
// 2. Patch operation (most efficient for partial updates)
await container.PatchItemAsync<TodoItem>(
"perf-typed",
new PartitionKey("test"),
new[] { PatchOperation.Replace("/title", "Patched") });
stopwatch.Stop();
Console.WriteLine($"Patch operation: {stopwatch.ElapsedMilliseconds}ms");
stopwatch.Restart();
// 3. JSON stream replace (fastest for full updates, no serialization)
string jsonUpdate = """{"id": "perf-json", "partitionKey": "test", "title": "JSON Updated"}""";
using var stream = new MemoryStream(Encoding.UTF8.GetBytes(jsonUpdate));
await container.ReplaceItemStreamAsync(stream, "perf-json", new PartitionKey("test"));
stopwatch.Stop();
Console.WriteLine($"Raw JSON replace: {stopwatch.ElapsedMilliseconds}ms");// Delete an item
try
{
await container.DeleteItemAsync<TodoItem>(
"task-1",
new PartitionKey("personal"));
Console.WriteLine("Item deleted successfully");
}
catch (CosmosException ex) when (ex.StatusCode == HttpStatusCode.NotFound)
{
Console.WriteLine("Item not found");
}
// Delete with optimistic concurrency
string etag = "\"00000000-0000-0000-0000-000000000000\""; // ETag from previous read
ItemRequestOptions deleteOptions = new ItemRequestOptions
{
IfMatchEtag = etag
};
await container.DeleteItemAsync<TodoItem>(
"task-1",
new PartitionKey("personal"),
deleteOptions);For high-throughput scenarios, Cosmos DB provides bulk operations through parallel tasks:
// Prepare items to create
List<TodoItem> itemsToCreate = new List<TodoItem>();
for (int i = 1; i <= 100; i++)
{
itemsToCreate.Add(new TodoItem
{
Id = $"bulk-task-{i}",
PartitionKey = "bulk",
Title = $"Bulk created item {i}",
Completed = false
});
}
// Create a list of tasks for parallel execution
List<Task> concurrentTasks = new List<Task>();
foreach (var item in itemsToCreate)
{
concurrentTasks.Add(container.CreateItemAsync(
item,
new PartitionKey(item.PartitionKey))
.ContinueWith(itemTask =>
{
if (itemTask.IsCompletedSuccessfully)
{
ItemResponse<TodoItem> response = itemTask.Result;
Console.WriteLine($"Created item {item.Id}: {response.RequestCharge} RUs");
}
else
{
AggregateException exceptions = itemTask.Exception;
Console.WriteLine($"Failed to create item {item.Id}: {exceptions.InnerException.Message}");
}
}));
}
// Wait for all operations to complete
await Task.WhenAll(concurrentTasks);The Change Feed is a powerful feature that provides a log of all changes to your containers:
// 1. Basic change feed processor
Container leaseContainer = await database.CreateContainerIfNotExistsAsync(
"leases",
"/id",
400);
var changeFeedProcessor = container.GetChangeFeedProcessorBuilder<TodoItem>(
processorName: "todoChanges",
onChangesDelegate: HandleChangesAsync)
.WithInstanceName("workerInstance1")
.WithLeaseContainer(leaseContainer)
.Build();
await changeFeedProcessor.StartAsync();
// Handle changes
async Task HandleChangesAsync(
ChangeFeedProcessorContext context,
IReadOnlyCollection<TodoItem> changes,
CancellationToken cancellationToken)
{
Console.WriteLine($"Detected {changes.Count} document changes");
foreach (TodoItem item in changes)
{
Console.WriteLine($"Changed item: {item.Id}, Title: {item.Title}");
// Process changes - update cache, trigger workflows, etc.
}
}
// Later - stop the processor
await changeFeedProcessor.StopAsync();CosmosDB supports stored procedures, triggers, and UDFs for server-side logic:
// 1. Create a stored procedure
string sprocId = "createTodoItem";
string sprocBody = @"
function createTodoItem(itemBody) {
var context = getContext();
var container = context.getCollection();
var response = context.getResponse();
// Generate ID if not provided
if (!itemBody.id) {
itemBody.id = generateGuid();
}
// Add creation timestamp
itemBody.createdAt = new Date().toISOString();
// Create document
var accepted = container.createDocument(
container.getSelfLink(),
itemBody,
function(err, documentCreated) {
if (err) throw new Error('Error: ' + err.message);
response.setBody(documentCreated);
}
);
if (!accepted) throw new Error('The item create was not accepted');
function generateGuid() {
return 'xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx'.replace(/[xy]/g, function(c) {
var r = Math.random() * 16 | 0, v = c == 'x' ? r : (r & 0x3 | 0x8);
return v.toString(16);
});
}
}";
StoredProcedureResponse response = await container.Scripts.CreateStoredProcedureAsync(
new StoredProcedureProperties
{
Id = sprocId,
Body = sprocBody
});
// 2. Execute a stored procedure
dynamic todoItem = new
{
partitionKey = "personal",
title = "Learn about stored procedures",
completed = false
};
StoredProcedureExecuteResponse<dynamic> executeResponse = await container.Scripts.ExecuteStoredProcedureAsync<dynamic>(
sprocId,
new PartitionKey("personal"),
new[] { todoItem });
dynamic createdItem = executeResponse.Resource;
Console.WriteLine($"Created item ID: {createdItem.id}");The Cosmos SDK has built-in retry policies, but you can customize them:
// Custom retry policy for handling rate limiting (429) errors
CosmosClientOptions options = new CosmosClientOptions
{
MaxRetryAttemptsOnRateLimitedRequests = 9,
MaxRetryWaitTimeOnRateLimitedRequests = TimeSpan.FromSeconds(30)
};
var cosmosClient = new CosmosClient(endpoint, key, options);For more complex scenarios, you can use Polly:
using Polly;
// Define policy
var retryPolicy = Policy
.Handle<CosmosException>(ex => ex.StatusCode == HttpStatusCode.TooManyRequests)
.WaitAndRetryAsync(
retryCount: 5,
sleepDurationProvider: (attempt) => TimeSpan.FromSeconds(Math.Pow(2, attempt)),
onRetry: (exception, timespan, retryCount, context) =>
{
Console.WriteLine($"Retry {retryCount} after {timespan.TotalSeconds}s due to {exception.Message}");
});
// Execute with policy
await retryPolicy.ExecuteAsync(async () =>
{
await container.CreateItemAsync(
newItem,
new PartitionKey(newItem.PartitionKey));
});// Program.cs or Startup.cs
using Microsoft.Azure.Cosmos;
using Microsoft.Extensions.DependencyInjection;
public void ConfigureServices(IServiceCollection services)
{
// Register CosmosClient as singleton
services.AddSingleton(serviceProvider =>
{
var configuration = serviceProvider.GetRequiredService<IConfiguration>();
return new CosmosClient(
configuration["CosmosDb:EndpointUrl"],
configuration["CosmosDb:PrimaryKey"],
new CosmosClientOptions
{
SerializerOptions = new CosmosSerializationOptions
{
PropertyNamingPolicy = CosmosPropertyNamingPolicy.CamelCase
}
});
});
// Register database and container clients
services.AddSingleton(serviceProvider =>
{
var cosmosClient = serviceProvider.GetRequiredService<CosmosClient>();
return cosmosClient.GetDatabase("MyDatabase");
});
services.AddSingleton(serviceProvider =>
{
var database = serviceProvider.GetRequiredService<Database>();
return database.GetContainer("TodoItems");
});
// Register your services
services.AddScoped<ITodoService, TodoService>();
}
// Service implementation
public interface ITodoService
{
Task<TodoItem> GetItemAsync(string id, string partitionKey);
Task<IEnumerable<TodoItem>> GetIncompleteItemsAsync(string partitionKey);
Task<TodoItem> CreateItemAsync(TodoItem item);
Task UpdateItemAsync(TodoItem item);
Task DeleteItemAsync(string id, string partitionKey);
}
public class TodoService : ITodoService
{
private readonly Container _container;
public TodoService(Container container)
{
_container = container;
}
public async Task<TodoItem> GetItemAsync(string id, string partitionKey)
{
try
{
var response = await _container.ReadItemAsync<TodoItem>(
id,
new PartitionKey(partitionKey));
return response.Resource;
}
catch (CosmosException ex) when (ex.StatusCode == HttpStatusCode.NotFound)
{
return null;
}
}
public async Task<IEnumerable<TodoItem>> GetIncompleteItemsAsync(string partitionKey)
{
var query = new QueryDefinition(
"SELECT * FROM c WHERE c.partitionKey = @pk AND c.completed = false")
.WithParameter("@pk", partitionKey);
var results = new List<TodoItem>();
var iterator = _container.GetItemQueryIterator<TodoItem>(
query,
requestOptions: new QueryRequestOptions
{
PartitionKey = new PartitionKey(partitionKey)
});
while (iterator.HasMoreResults)
{
var response = await iterator.ReadNextAsync();
results.AddRange(response);
}
return results;
}
public async Task<TodoItem> CreateItemAsync(TodoItem item)
{
var response = await _container.CreateItemAsync(
item,
new PartitionKey(item.PartitionKey));
return response.Resource;
}
// Additional methods...
}Azure Cosmos DB supports multiple authentication methods, each with its own security characteristics and use cases:
// Basic endpoint and key authentication
var endpoint = "https://your-account.documents.azure.com:443/";
var primaryKey = "your-primary-key";
var cosmosClient = new CosmosClient(endpoint, primaryKey);
// Alternative: Connection string
var connectionString = "AccountEndpoint=https://your-account.documents.azure.com:443/;AccountKey=your-primary-key;";
var cosmosClient = new CosmosClient(connectionString);Best for: Development environments, simple applications, single-service scenarios. Security considerations: Keys provide full access to the account and should be carefully protected.
using Azure.Identity;
// Using Managed Identity
var credential = new DefaultAzureCredential();
var cosmosClient = new CosmosClient(endpoint, credential);
// Using Service Principal
var servicePrincipalCredential = new ClientSecretCredential(
tenantId: "your-tenant-id",
clientId: "your-client-id",
clientSecret: "your-client-secret");
var cosmosClient = new CosmosClient(endpoint, servicePrincipalCredential);Best for: Production environments, multi-service applications, Azure-hosted services. Security considerations: No secrets in code, integrated with Azure RBAC, supports key rotation.
// First, create a permission (typically on a server with master key)
var permissionResponse = await container.CreatePermissionAsync(
new PermissionProperties
{
Id = "read-only-permission",
PermissionMode = PermissionMode.Read,
ResourceLink = container.Link,
ResourcePartitionKey = new PartitionKey("user123")
});
string resourceToken = permissionResponse.Resource.Token;
// On client side - use the limited resource token
var resourceTokenCosmosClient = new CosmosClient(
endpoint,
resourceToken,
new CosmosClientOptions
{
ApplicationRegion = "West US 2"
});Best for: Client-side applications, multi-tenant scenarios, granular access control. Security considerations: Fine-grained access control, short-lived tokens, limited to specific containers/partitions.
| Method | Security Level | Best For | Considerations |
|---|---|---|---|
| Primary Key | ⚠️ Basic | Development, Simple apps | Full account access, difficult to rotate |
| AAD Authentication | ✅ High | Production, Azure services | No secrets in code, easy to manage access |
| Managed Identity | ✅ Highest | Azure-hosted services | No secrets anywhere, automatic rotation |
| Resource Tokens | ✅ High | Client apps, Multi-tenant | Fine-grained, time-limited access |
Azure Cosmos DB has evolved significantly, and several legacy SDKs have been deprecated and discontinued. Understanding the migration path is crucial for maintaining secure, performant applications.
The original SDK for Cosmos DB SQL API, discontinued in March 2020.
A specialized SDK for accessing Cosmos DB Table API, based on Azure Table Storage patterns. Also deprecated in favor of the unified Microsoft.Azure.Cosmos approach.
The original Azure Table Storage SDK that many developers used before Cosmos DB Table API existed.
| Feature | Microsoft.Azure.DocumentDB |
Microsoft.Azure.Cosmos.Table |
Azure.Data.Tables |
Microsoft.Azure.Cosmos |
|---|---|---|---|---|
| Status | ❌ Deprecated (2020) | ❌ Deprecated (2021) | ✅ Active (Table Storage) | ✅ Active & Recommended |
| Target Service | Cosmos DB SQL API | Cosmos DB Table API | Azure Table Storage | All Cosmos DB APIs |
| API Design | Callback-heavy | Table Storage patterns | Modern async/await | Modern async/await |
| Performance | Poor | Moderate | Good | Excellent |
| Bulk Operations | Limited | Limited | Basic | Advanced |
| Authentication | Primary key only | Primary key + SAS | AAD + SAS + Key | AAD + Managed Identity + Key |
| .NET Core Support | Limited | Full | Full | Full |
| Multi-Model | SQL only | Table only | Table only | SQL, Table, MongoDB, etc. |
| Change Feed | Basic | ❌ Not supported | ❌ Not supported | Comprehensive |
| Global Distribution | Basic | Basic | ❌ Limited | Advanced |
| Diagnostics | Limited | Limited | Good | Excellent |
Step 1: Update Package References
<!-- REMOVE legacy package -->
<!-- <PackageReference Include="Microsoft.Azure.DocumentDB" Version="2.x.x" /> -->
<!-- ADD modern package -->
<PackageReference Include="Microsoft.Azure.Cosmos" Version="3.37.0" />Step 2: Update Namespace Imports
// OLD namespaces
// using Microsoft.Azure.Documents;
// using Microsoft.Azure.Documents.Client;
// NEW namespace
using Microsoft.Azure.Cosmos;Step 3: Update Client Initialization
// OLD - DocumentDB
/*
DocumentClient client = new DocumentClient(
new Uri("https://your-account.documents.azure.com:443/"),
"your-primary-key");
await client.OpenAsync();
*/
// NEW - Cosmos SDK
CosmosClient cosmosClient = new CosmosClient(
"https://your-account.documents.azure.com:443/",
"your-primary-key");Step 4: Update CRUD Operations
// OLD - Create Document
/*
Document document = await client.CreateDocumentAsync(
UriFactory.CreateDocumentCollectionUri("MyDatabase", "MyCollection"),
new { id = "item1", name = "Item 1", partitionKey = "pk1" });
*/
// NEW - Create Item
ItemResponse<dynamic> response = await container.CreateItemAsync<dynamic>(
new { id = "item1", name = "Item 1", partitionKey = "pk1" },
new PartitionKey("pk1"));
// OLD - Query Documents
/*
FeedOptions options = new FeedOptions { EnableCrossPartitionQuery = true };
IDocumentQuery<dynamic> query = client.CreateDocumentQuery<dynamic>(
UriFactory.CreateDocumentCollectionUri("MyDatabase", "MyCollection"),
"SELECT * FROM c WHERE c.name = 'Item 1'",
options).AsDocumentQuery();
while (query.HasMoreResults)
{
FeedResponse<dynamic> results = await query.ExecuteNextAsync<dynamic>();
foreach (var item in results)
{
Console.WriteLine(item.name);
}
}
*/
// NEW - Query Items
QueryDefinition queryDefinition = new QueryDefinition(
"SELECT * FROM c WHERE c.name = 'Item 1'");
FeedIterator<dynamic> resultSet = container.GetItemQueryIterator<dynamic>(
queryDefinition,
requestOptions: new QueryRequestOptions { MaxItemCount = 10 });
while (resultSet.HasMoreResults)
{
FeedResponse<dynamic> response = await resultSet.ReadNextAsync();
foreach (var item in response)
{
Console.WriteLine(item.name);
}
}Step 1: Update Package References
<!-- REMOVE legacy Table API package -->
<!-- <PackageReference Include="Microsoft.Azure.Cosmos.Table" Version="1.x.x" /> -->
<!-- ADD modern unified package -->
<PackageReference Include="Microsoft.Azure.Cosmos" Version="3.37.0" />Step 2: Update Namespace Imports
// OLD namespaces
// using Microsoft.Azure.Cosmos.Table;
// using Microsoft.Azure.Cosmos.Table.Protocol;
// NEW namespace
using Microsoft.Azure.Cosmos;Step 3: Client & Container Setup
// OLD - Table Client
/*
CloudStorageAccount storageAccount = CloudStorageAccount.Parse(connectionString);
CloudTableClient tableClient = storageAccount.CreateCloudTableClient();
CloudTable table = tableClient.GetTableReference("MyTable");
await table.CreateIfNotExistsAsync();
*/
// NEW - Cosmos Container (Table API via SQL API)
CosmosClient cosmosClient = new CosmosClient(endpoint, key);
Database database = await cosmosClient.CreateDatabaseIfNotExistsAsync("MyDatabase");
Container container = await database.CreateContainerIfNotExistsAsync(
id: "MyTable",
partitionKeyPath: "/PartitionKey", // Note: PartitionKey is the property name
throughput: 400);Step 4: Entity Model Changes
// OLD - Table Entity
/*
public class CustomerEntity : TableEntity
{
public CustomerEntity(string lastName, string firstName)
{
this.PartitionKey = lastName;
this.RowKey = firstName;
}
public CustomerEntity() { }
public string Email { get; set; }
public string PhoneNumber { get; set; }
}
*/
// NEW - Cosmos Document Model
public class Customer
{
[JsonProperty("id")]
public string Id { get; set; } // Combination of PartitionKey + RowKey
[JsonProperty("PartitionKey")]
public string PartitionKey { get; set; } // Same as Table PartitionKey
public string LastName { get; set; }
public string FirstName { get; set; }
public string Email { get; set; }
public string PhoneNumber { get; set; }
public DateTime Timestamp { get; set; } = DateTime.UtcNow;
// Constructor to maintain Table API compatibility
public Customer(string lastName, string firstName)
{
PartitionKey = lastName;
LastName = lastName;
FirstName = firstName;
Id = $"{lastName}#{firstName}"; // Composite key
}
public Customer() { }
}Step 5: CRUD Operations Migration
// OLD - Insert Entity
/*
CustomerEntity customer = new CustomerEntity("Doe", "John")
{
Email = "john.doe@example.com",
PhoneNumber = "555-1234"
};
TableOperation insertOperation = TableOperation.Insert(customer);
TableResult result = await table.ExecuteAsync(insertOperation);
*/
// NEW - Create Item
Customer customer = new Customer("Doe", "John")
{
Email = "john.doe@example.com",
PhoneNumber = "555-1234"
};
ItemResponse<Customer> response = await container.CreateItemAsync(
customer,
new PartitionKey(customer.PartitionKey));
// OLD - Retrieve Entity
/*
TableOperation retrieveOperation = TableOperation.Retrieve<CustomerEntity>("Doe", "John");
TableResult retrievedResult = await table.ExecuteAsync(retrieveOperation);
CustomerEntity customer = retrievedResult.Result as CustomerEntity;
*/
// NEW - Read Item
ItemResponse<Customer> response = await container.ReadItemAsync<Customer>(
"Doe#John", // Composite ID
new PartitionKey("Doe"));
Customer customer = response.Resource;
// OLD - Query Entities
/*
TableQuery<CustomerEntity> query = new TableQuery<CustomerEntity>()
.Where(TableQuery.GenerateFilterCondition("PartitionKey", QueryComparisons.Equal, "Doe"));
TableContinuationToken token = null;
var customers = new List<CustomerEntity>();
do
{
TableQuerySegment<CustomerEntity> segment = await table.ExecuteQuerySegmentedAsync(query, token);
customers.AddRange(segment.Results);
token = segment.ContinuationToken;
} while (token != null);
*/
// NEW - Query Items
QueryDefinition query = new QueryDefinition(
"SELECT * FROM c WHERE c.PartitionKey = @partitionKey")
.WithParameter("@partitionKey", "Doe");
FeedIterator<Customer> resultSet = container.GetItemQueryIterator<Customer>(
query,
requestOptions: new QueryRequestOptions
{
PartitionKey = new PartitionKey("Doe")
});
List<Customer> customers = new List<Customer>();
while (resultSet.HasMoreResults)
{
FeedResponse<Customer> response = await resultSet.ReadNextAsync();
customers.AddRange(response);
}If you’re coming from Azure Table Storage and want to access Cosmos DB:
Option A: Stay with Table Storage using Azure.Data.Tables
<PackageReference Include="Azure.Data.Tables" Version="12.8.0" />Option B: Migrate to Cosmos DB with Microsoft.Azure.Cosmos
<PackageReference Include="Microsoft.Azure.Cosmos" Version="3.37.0" />The migration from WindowsAzure.Storage to Azure.Data.Tables is straightforward and maintains Table API semantics. However, migrating to Cosmos DB provides global distribution, better performance, and additional features.
| Current SDK | Target Service | Recommended Path | Complexity | Benefits |
|---|---|---|---|---|
| Microsoft.Azure.DocumentDB | Cosmos DB SQL | → Microsoft.Azure.Cosmos |
Medium | Modern API, Performance, Features |
| Microsoft.Azure.Cosmos.Table | Cosmos DB Table | → Microsoft.Azure.Cosmos |
High | Unified SDK, Better Performance |
| Microsoft.Azure.Cosmos.Table | Azure Table Storage | → Azure.Data.Tables |
Low | Modern Table API, Simpler Migration |
| WindowsAzure.Storage | Azure Table Storage | → Azure.Data.Tables |
Low | Modern SDK, Better Performance |
| WindowsAzure.Storage | Cosmos DB | → Microsoft.Azure.Cosmos |
High | Global Distribution, Advanced Features |
PartitionKey/RowKey to composite id fieldTableEntity base class with POCO modelsMoving to Microsoft.Azure.Cosmos provides:
✅ Unified Experience - Single SDK for all Cosmos DB APIs
✅ Better Performance - Optimized for modern async patterns
✅ Advanced Features - Bulk operations, change feed, global distribution
✅ Enhanced Authentication - AAD, Managed Identity, fine-grained access
✅ Rich Diagnostics - Detailed metrics and performance insights
✅ Future-Proof - Active development and new feature support
| SDK | Final Version | End of Support | Security Updates | Recommendation |
|---|---|---|---|---|
Microsoft.Azure.DocumentDB |
2.18.0 | March 2020 | ❌ None | ⚠️ Migrate immediately |
Microsoft.Azure.Cosmos.Table |
1.0.8 | August 2021 | ❌ None | ⚠️ Migrate immediately |
WindowsAzure.Storage |
9.3.3 | November 2023 | ❌ None | ⚠️ Migrate immediately |
Azure.Data.Tables |
Current | ✅ Active | ✅ Yes | ✅ Use for Table Storage |
Microsoft.Azure.Cosmos |
Current | ✅ Active | ✅ Yes | ✅ Use for Cosmos DB |
⚠️ Important: Microsoft will not provide security updates or bug fixes for legacy SDKs. Migration to
Microsoft.Azure.Cosmosis strongly recommended for security and compatibility reasons.
Official Documentation: Azure Cosmos DB Documentation
Comprehensive documentation covering Azure Cosmos DB concepts, capabilities, APIs, and service-level features. Essential for understanding provisioning models, consistency levels, indexing policies, and architectural considerations for designing Cosmos DB solutions.
SDK Reference: Microsoft.Azure.Cosmos SDK Reference
Complete API reference documentation for the Microsoft.Azure.Cosmos SDK, including all classes, methods, properties, and their signatures. Critical development resource for understanding method parameters, return types, exceptions, and proper usage patterns when writing Cosmos DB applications.
Code Samples: Azure Cosmos DB .NET SDK Samples
Official code samples demonstrating real-world implementation patterns, performance optimization techniques, and advanced scenarios like change feed processing and bulk operations. Provides practical examples of best practices, error handling, and common use cases.
Performance Tips: Performance Tips for Azure Cosmos DB
Expert guidance on optimizing your applications for maximum performance and cost-efficiency with Azure Cosmos DB, including connection management, query optimization, indexing strategies, and RU optimization techniques to ensure your applications run efficiently.
Migration Guide: Migrating from DocumentDB SDK to Cosmos DB SDK
Detailed migration guide for transitioning from the legacy Microsoft.Azure.DocumentDB SDK to the modern Microsoft.Azure.Cosmos SDK, with code comparisons, breaking change explanations, and step-by-step migration strategies.
The Microsoft.Azure.Cosmos SDK is the recommended approach for accessing Azure Cosmos DB from C#. It provides:
Azure Cosmos DB offers a globally distributed, multi-model database service with comprehensive SLAs for throughput, latency, availability, and consistency, making it ideal for modern cloud applications requiring global scale and low latency.