Azure Tables input bindings for Azure Functions

Article
08/21/2024

Use the Azure Tables input binding to read a table in Azure Cosmos DB for Table or Azure Table Storage.

For information on setup and configuration details, see the overview.

Important

This article uses tabs to support multiple versions of the Node.js programming model. The v4 model is currently in preview and is designed to have a more flexible and intuitive experience for JavaScript and TypeScript developers. Learn more about the differences between v3 and v4 in the upgrade guide.

Example

The usage of the binding depends on the extension package version and the C# modality used in your function app, which can be one of the following:

Isolated worker model
In-process model

An isolated worker process class library compiled C# function runs in a process isolated from the runtime.

Choose a version to see examples for the mode and version.

The following example shows a C# function that reads a single table row. For every message sent to the queue, the function will be triggered.

The row key value {queueTrigger} binds the row key to the message metadata, which is the message string.

public class TableStorage
{
    public class MyPoco : Azure.Data.Tables.ITableEntity
    {
        public string Text { get; set; }

        public string PartitionKey { get; set; }
        public string RowKey { get; set; }
        public DateTimeOffset? Timestamp { get; set; }
        public ETag ETag { get; set; }
    }


    [FunctionName("TableInput")]
    public static void TableInput(
        [QueueTrigger("table-items")] string input, 
        [Table("MyTable", "MyPartition", "{queueTrigger}")] MyPoco poco, 
        ILogger log)
    {
        log.LogInformation($"PK={poco.PartitionKey}, RK={poco.RowKey}, Text={poco.Text}");
    }
}

Use a TableClient method parameter to read the table by using the Azure SDK. Here's an example of a function that queries an Azure Functions log table:

using Microsoft.Azure.WebJobs;
using Microsoft.Extensions.Logging;
using Azure.Data.Tables;
using System;
using System.Threading.Tasks;
using Azure;
namespace FunctionAppCloudTable2
{
    public class LogEntity : ITableEntity
    {
        public string OriginalName { get; set; }

        public string PartitionKey { get; set; }
        public string RowKey { get; set; }
        public DateTimeOffset? Timestamp { get; set; }
        public ETag ETag { get; set; }
    }
    public static class CloudTableDemo
    {
        [FunctionName("CloudTableDemo")]
        public static async Task Run(
            [TimerTrigger("0 */1 * * * *")] TimerInfo myTimer,
            [Table("AzureWebJobsHostLogscommon")] TableClient tableClient,
            ILogger log)
        {
            log.LogInformation($"C# Timer trigger function executed at: {DateTime.Now}");
            AsyncPageable<LogEntity> queryResults = tableClient.QueryAsync<LogEntity>(filter: $"PartitionKey eq 'FD2' and RowKey gt 't'");
            await foreach (LogEntity entity in queryResults)
            {
                log.LogInformation($"{entity.PartitionKey}\t{entity.RowKey}\t{entity.Timestamp}\t{entity.OriginalName}");
            }
        }
    }
}

For more information about how to use TableClient, see the Azure.Data.Tables API Reference.

The following example shows a C# function that reads a single table row. For every message sent to the queue, the function will be triggered.

The row key value {queueTrigger} binds the row key to the message metadata, which is the message string.

public class TableStorage
{
    public class MyPoco
    {
        public string PartitionKey { get; set; }
        public string RowKey { get; set; }
        public string Text { get; set; }
    }

    [FunctionName("TableInput")]
    public static void TableInput(
        [QueueTrigger("table-items")] string input, 
        [Table("MyTable", "MyPartition", "{queueTrigger}")] MyPoco poco, 
        ILogger log)
    {
        log.LogInformation($"PK={poco.PartitionKey}, RK={poco.RowKey}, Text={poco.Text}");
    }
}

Use a CloudTable method parameter to read the table by using the Azure Storage SDK. Here's an example of a function that queries an Azure Functions log table:

using Microsoft.Azure.WebJobs;
using Microsoft.Azure.WebJobs.Host;
using Microsoft.Extensions.Logging;
using Microsoft.Azure.Cosmos.Table;
using System;
using System.Threading.Tasks;

namespace FunctionAppCloudTable2
{
    public class LogEntity : TableEntity
    {
        public string OriginalName { get; set; }
    }
    public static class CloudTableDemo
    {
        [FunctionName("CloudTableDemo")]
        public static async Task Run(
            [TimerTrigger("0 */1 * * * *")] TimerInfo myTimer, 
            [Table("AzureWebJobsHostLogscommon")] CloudTable cloudTable,
            ILogger log)
        {
            log.LogInformation($"C# Timer trigger function executed at: {DateTime.Now}");

            TableQuery<LogEntity> rangeQuery = new TableQuery<LogEntity>().Where(
                TableQuery.CombineFilters(
                    TableQuery.GenerateFilterCondition("PartitionKey", QueryComparisons.Equal, 
                        "FD2"),
                    TableOperators.And,
                    TableQuery.GenerateFilterCondition("RowKey", QueryComparisons.GreaterThan, 
                        "t")));

            // Execute the query and loop through the results
            foreach (LogEntity entity in 
                await cloudTable.ExecuteQuerySegmentedAsync(rangeQuery, null))
            {
                log.LogInformation(
                    $"{entity.PartitionKey}\t{entity.RowKey}\t{entity.Timestamp}\t{entity.OriginalName}");
            }
        }
    }
}

For more information about how to use CloudTable, see Get started with Azure Table storage.

If you try to bind to CloudTable and get an error message, make sure that you have a reference to the correct Storage SDK version.

The following example shows a C# function that reads a single table row. For every message sent to the queue, the function will be triggered.

The row key value {queueTrigger} binds the row key to the message metadata, which is the message string.

public class TableStorage
{
    public class MyPoco
    {
        public string PartitionKey { get; set; }
        public string RowKey { get; set; }
        public string Text { get; set; }
    }

    [FunctionName("TableInput")]
    public static void TableInput(
        [QueueTrigger("table-items")] string input, 
        [Table("MyTable", "MyPartition", "{queueTrigger}")] MyPoco poco, 
        ILogger log)
    {
        log.LogInformation($"PK={poco.PartitionKey}, RK={poco.RowKey}, Text={poco.Text}");
    }
}

The following example shows a C# function that reads multiple table rows where the MyPoco class derives from TableEntity.

public class TableStorage
{
    public class MyPoco : TableEntity
    {
        public string Text { get; set; }
    }

    [FunctionName("TableInput")]
    public static void TableInput(
        [QueueTrigger("table-items")] string input, 
        [Table("MyTable", "MyPartition")] IQueryable<MyPoco> pocos, 
        ILogger log)
    {
        foreach (MyPoco poco in pocos)
        {
            log.LogInformation($"PK={poco.PartitionKey}, RK={poco.RowKey}, Text={poco.Text}");
        }
    }
}

The following MyTableData class represents a row of data in the table:

public class MyTableData : Azure.Data.Tables.ITableEntity
{
    public string Text { get; set; }

    public string PartitionKey { get; set; }
    public string RowKey { get; set; }
    public DateTimeOffset? Timestamp { get; set; }
    public ETag ETag { get; set; }
}

The following function, which is started by a Queue Storage trigger, reads a row key from the queue, which is used to get the row from the input table. The expression {queueTrigger} binds the row key to the message metadata, which is the message string.

[Function("TableFunction")]
[TableOutput("OutputTable", Connection = "AzureWebJobsStorage")]
public static MyTableData Run(
    [QueueTrigger("table-items")] string input,
    [TableInput("MyTable", "<PartitionKey>", "{queueTrigger}")] MyTableData tableInput,
    FunctionContext context)
{
    var logger = context.GetLogger("TableFunction");

    logger.LogInformation($"PK={tableInput.PartitionKey}, RK={tableInput.RowKey}, Text={tableInput.Text}");

    return new MyTableData()
    {
        PartitionKey = "queue",
        RowKey = Guid.NewGuid().ToString(),
        Text = $"Output record with rowkey {input} created at {DateTime.Now}"
    };
}

The following Queue-triggered function returns the first 5 entities as an IEnumerable<T>, with the partition key value set as the queue message.

[Function("TestFunction")]
public static void Run([QueueTrigger("myqueue", Connection = "AzureWebJobsStorage")] string partition,
    [TableInput("inTable", "{queueTrigger}", Take = 5, Filter = "Text eq 'test'", 
    Connection = "AzureWebJobsStorage")] IEnumerable<MyTableData> tableInputs,
    FunctionContext context)
{
    var logger = context.GetLogger("TestFunction");
    logger.LogInformation(partition);
    foreach (MyTableData tableInput in tableInputs)
    {
        logger.LogInformation($"PK={tableInput.PartitionKey}, RK={tableInput.RowKey}, Text={tableInput.Text}");
    }
}

The Filter and Take properties are used to limit the number of entities returned.

The following MyTableData class represents a row of data in the table:

        {
            var tableEntities = table.QueryAsync<TableEntity>(filter: $"RowKey eq '{rowKey}'");

            await foreach (TableEntity entity in tableEntities)
            {
                _logger.LogInformation("PK={pk}, RK={rk}, Text={t}", entity.PartitionKey, entity.RowKey, entity["Text"]);
            }

namespace SampleApp
{
    public class TableFunction
    {
        private readonly ILogger<TableFunction> _logger;

        public TableFunction(ILogger<TableFunction> logger)
        {
            _logger = logger;
        }

        /// <summary>
        /// This function demonstrates binding to a single <see cref="TableClient"/>
        /// and using the client for output.
        /// </summary>
        [Function(nameof(TableFunction))]
        public async Task Run(
            [QueueTrigger("table-items")] string rowKey,

The following Queue-triggered function returns the first 5 entities as an IEnumerable<T>, with the partition key value set as the queue message.

[Function("TestFunction")]
public static void Run([QueueTrigger("myqueue", Connection = "AzureWebJobsStorage")] string partition,
    [TableInput("inTable", "{queueTrigger}", Take = 5, Filter = "Text eq 'test'", 
    Connection = "AzureWebJobsStorage")] IEnumerable<MyTableData> tableInputs,
    FunctionContext context)
{
    var logger = context.GetLogger("TestFunction");
    logger.LogInformation(partition);
    foreach (MyTableData tableInput in tableInputs)
    {
        logger.LogInformation($"PK={tableInput.PartitionKey}, RK={tableInput.RowKey}, Text={tableInput.Text}");
    }
}

The Filter and Take properties are used to limit the number of entities returned.

The following example shows an HTTP triggered function which returns a list of person objects who are in a specified partition in Table storage. In the example, the partition key is extracted from the http route, and the tableName and connection are from the function settings.

public class Person {
    private String PartitionKey;
    private String RowKey;
    private String Name;

    public String getPartitionKey() { return this.PartitionKey; }
    public void setPartitionKey(String key) { this.PartitionKey = key; }
    public String getRowKey() { return this.RowKey; }
    public void setRowKey(String key) { this.RowKey = key; }
    public String getName() { return this.Name; }
    public void setName(String name) { this.Name = name; }
}

@FunctionName("getPersonsByPartitionKey")
public Person[] get(
        @HttpTrigger(name = "getPersons", methods = {HttpMethod.GET}, authLevel = AuthorizationLevel.FUNCTION, route="persons/{partitionKey}") HttpRequestMessage<Optional<String>> request,
        @BindingName("partitionKey") String partitionKey,
        @TableInput(name="persons", partitionKey="{partitionKey}", tableName="%MyTableName%", connection="MyConnectionString") Person[] persons,
        final ExecutionContext context) {

    context.getLogger().info("Got query for person related to persons with partition key: " + partitionKey);

    return persons;
}

The TableInput annotation can also extract the bindings from the json body of the request, like the following example shows.

@FunctionName("GetPersonsByKeysFromRequest")
public HttpResponseMessage get(
        @HttpTrigger(name = "getPerson", methods = {HttpMethod.GET}, authLevel = AuthorizationLevel.FUNCTION, route="query") HttpRequestMessage<Optional<String>> request,
        @TableInput(name="persons", partitionKey="{partitionKey}", rowKey = "{rowKey}", tableName="%MyTableName%", connection="MyConnectionString") Person person,
        final ExecutionContext context) {

    if (person == null) {
        return request.createResponseBuilder(HttpStatus.NOT_FOUND)
                    .body("Person not found.")
                    .build();
    }

    return request.createResponseBuilder(HttpStatus.OK)
                    .header("Content-Type", "application/json")
                    .body(person)
                    .build();
}

The following example uses a filter to query for persons with a specific name in an Azure Table, and limits the number of possible matches to 10 results.

@FunctionName("getPersonsByName")
public Person[] get(
        @HttpTrigger(name = "getPersons", methods = {HttpMethod.GET}, authLevel = AuthorizationLevel.FUNCTION, route="filter/{name}") HttpRequestMessage<Optional<String>> request,
        @BindingName("name") String name,
        @TableInput(name="persons", filter="Name eq '{name}'", take = "10", tableName="%MyTableName%", connection="MyConnectionString") Person[] persons,
        final ExecutionContext context) {

    context.getLogger().info("Got query for person related to persons with name: " + name);

    return persons;
}

The following example shows a table input binding that uses a queue trigger to read a single table row. The binding specifies a partitionKey and a rowKey. The rowKey value "{queueTrigger}" indicates that the row key comes from the queue message string.

Model v4
Model v3

import { app, input, InvocationContext } from '@azure/functions';

const tableInput = input.table({
    tableName: 'Person',
    partitionKey: 'Test',
    rowKey: '{queueTrigger}',
    connection: 'MyStorageConnectionAppSetting',
});

interface PersonEntity {
    PartitionKey: string;
    RowKey: string;
    Name: string;
}

export async function storageQueueTrigger1(queueItem: unknown, context: InvocationContext): Promise<void> {
    context.log('Node.js queue trigger function processed work item', queueItem);
    const person = <PersonEntity>context.extraInputs.get(tableInput);
    context.log('Person entity name: ' + person.Name);
}

app.storageQueue('storageQueueTrigger1', {
    queueName: 'myqueue-items',
    connection: 'MyStorageConnectionAppSetting',
    extraInputs: [tableInput],
    handler: storageQueueTrigger1,
});

Model v4
Model v3

const { app, input } = require('@azure/functions');

const tableInput = input.table({
    tableName: 'Person',
    partitionKey: 'Test',
    rowKey: '{queueTrigger}',
    connection: 'MyStorageConnectionAppSetting',
});

app.storageQueue('storageQueueTrigger1', {
    queueName: 'myqueue-items',
    connection: 'MyStorageConnectionAppSetting',
    extraInputs: [tableInput],
    handler: (queueItem, context) => {
        context.log('Node.js queue trigger function processed work item', queueItem);
        const person = context.extraInputs.get(tableInput);
        context.log('Person entity name: ' + person.Name);
    },
});

{
  "bindings": [
    {
      "queueName": "myqueue-items",
      "connection": "MyStorageConnectionAppSetting",
      "name": "myQueueItem",
      "type": "queueTrigger",
      "direction": "in"
    },
    {
      "name": "personEntity",
      "type": "table",
      "tableName": "Person",
      "partitionKey": "Test",
      "rowKey": "{queueTrigger}",
      "connection": "MyStorageConnectionAppSetting",
      "direction": "in"
    }
  ],
  "disabled": false
}

The configuration section explains these properties.

Here's the JavaScript code:

module.exports = async function (context, myQueueItem) {
    context.log('Node.js queue trigger function processed work item', myQueueItem);
    context.log('Person entity name: ' + context.bindings.personEntity.Name);
};

The following function uses a queue trigger to read a single table row as input to a function.

In this example, the binding configuration specifies an explicit value for the table's partitionKey and uses an expression to pass to the rowKey. The rowKey expression, {queueTrigger}, indicates that the row key comes from the queue message string.

Binding configuration in function.json:

{
  "bindings": [
    {
      "queueName": "myqueue-items",
      "connection": "MyStorageConnectionAppSetting",
      "name": "MyQueueItem",
      "type": "queueTrigger",
      "direction": "in"
    },
    {
      "name": "PersonEntity",
      "type": "table",
      "tableName": "Person",
      "partitionKey": "Test",
      "rowKey": "{queueTrigger}",
      "connection": "MyStorageConnectionAppSetting",
      "direction": "in"
    }
  ],
  "disabled": false
}

PowerShell code in run.ps1:

param($MyQueueItem, $PersonEntity, $TriggerMetadata)
Write-Host "PowerShell queue trigger function processed work item: $MyQueueItem"
Write-Host "Person entity name: $($PersonEntity.Name)"

The following function uses an HTTP trigger to read a single table row as input to a function.

In this example, binding configuration specifies an explicit value for the table's partitionKey and uses an expression to pass to the rowKey. The rowKey expression, {id} indicates that the row key comes from the {id} part of the route in the request.

Binding configuration in the function.json file:

{
  "scriptFile": "__init__.py",
  "bindings": [
    {
      "name": "messageJSON",
      "type": "table",
      "tableName": "messages",
      "partitionKey": "message",
      "rowKey": "{id}",
      "connection": "AzureWebJobsStorage",
      "direction": "in"
    },
    {
      "authLevel": "function",
      "type": "httpTrigger",
      "direction": "in",
      "name": "req",
      "methods": [
        "get",
        "post"
      ],
      "route": "messages/{id}"
    },
    {
      "type": "http",
      "direction": "out",
      "name": "$return"
    }
  ],
  "disabled": false
}

Python code in the __init__.py file:

import json

import azure.functions as func

def main(req: func.HttpRequest, messageJSON) -> func.HttpResponse:

    message = json.loads(messageJSON)
    return func.HttpResponse(f"Table row: {messageJSON}")

With this simple binding, you can't programmatically handle a case in which no row that has a row key ID is found. For more fine-grained data selection, use the storage SDK.

Attributes

Both in-process and isolated worker process C# libraries use attributes to define the function. C# script instead uses a function.json configuration file as described in the C# scripting guide.

Isolated worker model
In-process model

In C# class libraries, the TableInputAttribute supports the following properties:

Attribute property	Description
TableName	The name of the table.
PartitionKey	Optional. The partition key of the table entity to read.
RowKey	Optional. The row key of the table entity to read.
Take	Optional. The maximum number of entities to read into an `IEnumerable<T>`. Can't be used with `RowKey`.
Filter	Optional. An OData filter expression for entities to read into an `IEnumerable<T>`. Can't be used with `RowKey`.
Connection	The name of an app setting or setting collection that specifies how to connect to the table service. See Connections.

In C# class libraries, the TableAttribute supports the following properties:

Attribute property	Description
TableName	The name of the table.
PartitionKey	Optional. The partition key of the table entity to read. See the usage section for guidance on how to use this property.
RowKey	Optional. The row key of a single table entity to read. Can't be used with `Take` or `Filter`.
Take	Optional. The maximum number of entities to return. Can't be used with `RowKey`.
Filter	Optional. An OData filter expression for the entities to return from the table. Can't be used with `RowKey`.
Connection	The name of an app setting or setting collection that specifies how to connect to the table service. See Connections.

The attribute's constructor takes the table name, partition key, and row key, as shown in the following example:

[FunctionName("TableInput")]
public static void Run(
    [QueueTrigger("table-items")] string input, 
    [Table("MyTable", "Http", "{queueTrigger}")] MyPoco poco, 
    ILogger log)
{
    ...
}

You can set the Connection property to specify the connection to the table service, as shown in the following example:

[FunctionName("TableInput")]
public static void Run(
    [QueueTrigger("table-items")] string input, 
    [Table("MyTable", "Http", "{queueTrigger}", Connection = "StorageConnectionAppSetting")] MyPoco poco, 
    ILogger log)
{
    ...
}

While the attribute takes a Connection property, you can also use the StorageAccountAttribute to specify a storage account connection. You can do this when you need to use a different storage account than other functions in the library. The constructor takes the name of an app setting that contains a storage connection string. The attribute can be applied at the parameter, method, or class level. The following example shows class level and method level:

[StorageAccount("ClassLevelStorageAppSetting")]
public static class AzureFunctions
{
    [FunctionName("StorageTrigger")]
    [StorageAccount("FunctionLevelStorageAppSetting")]
    public static void Run( //...
{
    ...
}

The storage account to use is determined in the following order:

The trigger or binding attribute's Connection property.
The StorageAccount attribute applied to the same parameter as the trigger or binding attribute.
The StorageAccount attribute applied to the function.
The StorageAccount attribute applied to the class.
The default storage account for the function app, which is defined in the AzureWebJobsStorage application setting.

Annotations

In the Java functions runtime library, use the @TableInput annotation on parameters whose value would come from Table storage. This annotation can be used with native Java types, POJOs, or nullable values using Optional<T>. This annotation supports the following elements:

Element	Description
name	The name of the variable that represents the table or entity in function code.
tableName	The name of the table.
partitionKey	Optional. The partition key of the table entity to read.
rowKey	Optional. The row key of the table entity to read.
take	Optional. The maximum number of entities to read.
filter	Optional. An OData filter expression for table input.
connection	The name of an app setting or setting collection that specifies how to connect to the table service. See Connections.

The following table explains the properties that you can set on the options object passed to the input.table() method.

Property	Description
tableName	The name of the table.
partitionKey	Optional. The partition key of the table entity to read.
rowKey	Optional. The row key of the table entity to read. Can't be used with `take` or `filter`.
take	Optional. The maximum number of entities to return. Can't be used with `rowKey`.
filter	Optional. An OData filter expression for the entities to return from the table. Can't be used with `rowKey`.
connection	The name of an app setting or setting collection that specifies how to connect to the table service. See Connections.

The following table explains the binding configuration properties that you set in the function.json file.

Property	Description
type	Must be set to `table`. This property is set automatically when you create the binding in the Azure portal.
direction	Must be set to `in`. This property is set automatically when you create the binding in the Azure portal.
name	The name of the variable that represents the table or entity in function code.
tableName	The name of the table.
partitionKey	Optional. The partition key of the table entity to read.
rowKey	Optional. The row key of the table entity to read. Can't be used with `take` or `filter`.
take	Optional. The maximum number of entities to return. Can't be used with `rowKey`.
filter	Optional. An OData filter expression for the entities to return from the table. Can't be used with `rowKey`.
connection	The name of an app setting or setting collection that specifies how to connect to the table service. See Connections.

Configuration

The following table explains the binding configuration properties that you set in the function.json file.

function.json property	Description
type	Must be set to `table`. This property is set automatically when you create the binding in the Azure portal.
direction	Must be set to `in`. This property is set automatically when you create the binding in the Azure portal.
name	The name of the variable that represents the table or entity in function code.
tableName	The name of the table.
partitionKey	Optional. The partition key of the table entity to read.
rowKey	Optional. The row key of the table entity to read. Can't be used with `take` or `filter`.
take	Optional. The maximum number of entities to return. Can't be used with `rowKey`.
filter	Optional. An OData filter expression for the entities to return from the table. Can't be used with `rowKey`.
connection	The name of an app setting or setting collection that specifies how to connect to the table service. See Connections.

When you're developing locally, add your application settings in the local.settings.json file in the Values collection.

Connections

The connection property is a reference to environment configuration that specifies how the app should connect to your table service. It may specify:

The name of an application setting containing a connection string
The name of a shared prefix for multiple application settings, together defining an identity-based connection

If the configured value is both an exact match for a single setting and a prefix match for other settings, the exact match is used.

Connection string

To obtain a connection string for tables in Azure Table storage, follow the steps shown at Manage storage account access keys. To obtain a connection string for tables in Azure Cosmos DB for Table, follow the steps shown at the Azure Cosmos DB for Table FAQ.

This connection string should be stored in an application setting with a name matching the value specified by the connection property of the binding configuration.

If the app setting name begins with "AzureWebJobs", you can specify only the remainder of the name here. For example, if you set connection to "MyStorage", the Functions runtime looks for an app setting that is named "AzureWebJobsMyStorage". If you leave connection empty, the Functions runtime uses the default Storage connection string in the app setting that is named AzureWebJobsStorage.

Identity-based connections

If you're using the Tables API extension, instead of using a connection string with a secret, you can have the app use an Azure Active Directory identity. This only applies when accessing tables in Azure Storage. To use an identity, you define settings under a common prefix that maps to the connection property in the trigger and binding configuration.

If you're setting connection to "AzureWebJobsStorage", see Connecting to host storage with an identity. For all other connections, the extension requires the following properties:

Property	Environment variable template	Description	Example value
Table Service URI	`<CONNECTION_NAME_PREFIX>__tableServiceUri`¹	The data plane URI of the Azure Storage table service to which you're connecting, using the HTTPS scheme.	https://<storage_account_name>.table.core.chinacloudapi.cn

¹ <CONNECTION_NAME_PREFIX>__serviceUri can be used as an alias. If both forms are provided, the tableServiceUri form is used. The serviceUri form can't be used when the overall connection configuration is to be used across blobs, queues, and/or tables.

Other properties may be set to customize the connection. See Common properties for identity-based connections.

The serviceUri form can't be used when the overall connection configuration is to be used across blobs, queues, and/or tables in Azure Storage. The URI can only designate the table service. As an alternative, you can provide a URI specifically for each service under the same prefix, allowing a single connection to be used.

When hosted in the Azure Functions service, identity-based connections use a managed identity. The system-assigned identity is used by default, although a user-assigned identity can be specified with the credential and clientID properties. Note that configuring a user-assigned identity with a resource ID is not supported. When run in other contexts, such as local development, your developer identity is used instead, although this can be customized. See Local development with identity-based connections.

Grant permission to the identity

Whatever identity is being used must have permissions to perform the intended actions. You will need to assign a role in Azure RBAC, using either built-in or custom roles which provide those permissions.

Important

Some permissions might be exposed by the target service that are not necessary for all contexts. Where possible, adhere to the principle of least privilege, granting the identity only required privileges. For example, if the app only needs to be able to read from a data source, use a role that only has permission to read. It would be inappropriate to assign a role that also allows writing to that service, as this would be excessive permission for a read operation. Similarly, you would want to ensure the role assignment is scoped only over the resources that need to be read.

You will need to create a role assignment that provides access to your Azure Storage table service at runtime. Management roles like Owner are not sufficient. The following table shows built-in roles that are recommended when using the Azure Cosmos DB for Table extension against Azure Storage in normal operation. Your application may require additional permissions based on the code you write.

Binding type	Example built-in roles (Azure Storage¹)
Input binding	Storage Table Data Reader
Output binding	Storage Table Data Contributor

¹ If your app is instead connecting to tables in Azure Cosmos DB for Table, using an identity is not supported and the connection must use a connection string.

Usage

The usage of the binding depends on the extension package version, and the C# modality used in your function app, which can be one of the following:

Isolated worker model
In-process model

An isolated worker process class library compiled C# function runs in a process isolated from the runtime.

Choose a version to see usage details for the mode and version.

When working with a single table entity, the Azure Tables input binding can bind to the following types:

Type	Description
A JSON serializable type that implements ITableEntity	Functions attempts to deserialize the entity into a plain-old CLR object (POCO) type. The type must implement ITableEntity or have a string `RowKey` property and a string `PartitionKey` property.
TableEntity	(Preview¹) The entity as a dictionary-like type.

When working with multiple entities from a query, the Azure Tables input binding can bind to the following types:

Type	Description
`IEnumerable<T>` where `T` implements ITableEntity	An enumeration of entities returned by the query. Each entry represents one entity. The type `T` must implement ITableEntity or have a string `RowKey` property and a string `PartitionKey` property.
TableClient	(Preview¹) A client connected to the table. This offers the most control for processing the table and can be used to write to it if the connection has sufficient permission.

¹ To use these types, you need to reference Microsoft.Azure.Functions.Worker.Extensions.Tables 1.2.0-preview1 or later and the common dependencies for SDK type bindings.

The TableInput attribute gives you access to the table row that triggered the function.

Model v4
Model v3

Get the input row data by using context.extraInputs.get().

Data is passed to the input parameter as specified by the name key in the function.json file. Specifying The partitionKey and rowKey allows you to filter to specific records.

Table data is passed to the function as a JSON string. De-serialize the message by calling json.loads as shown in the input example.

For specific usage details, see Example.

Next steps

Write table data from a function

Azure Tables input bindings for Azure Functions

Example

Attributes

Annotations

Configuration

Configuration

Connections

Connection string

Identity-based connections

Grant permission to the identity

Usage

Next steps

Additional resources