从 azure table 存储中获取所有记录

Question

使用这个代码块

try
{
    StorageCredentials creds = new StorageCredentials(accountName, accountKey);
    CloudStorageAccount account = new CloudStorageAccount(creds, useHttps: true);

    CloudTableClient client = account.CreateCloudTableClient();
    CloudTable table = client.GetTableReference("serviceAlerts");

    TableOperation retrieveOperation = TableOperation.Retrieve<ServiceAlertsEntity>("ServiceAlerts", "b9ccd839-dd99-4358-b90f-46781b87f933");

    TableResult query = table.Execute(retrieveOperation);

    if (query.Result != null)
    {
        outline = outline + ((ServiceAlertsEntity) query.Result).alertMessage + " * ";
    }
    else
    {
        Console.WriteLine("No Alerts");
    }
}
catch (Exception ex)
{
    Console.WriteLine(ex);
}

我能够使用检索中提到的分区和行键检索单个记录。

有什么方法可以获取存储在 ServiceAlerts 分区中的所有记录？

我试过为第二个参数使用通配符 (*)

TableOperation retrieveOperation = TableOperation.Retrieve<ServiceAlertsEntity>(
      "ServiceAlerts","b9ccd839-dd99-4358-b90f-46781b87f933");

但它没有return任何东西。

Answer 1

你用错了class。使用 TableQuery 检索多个结果。 https://msdn.microsoft.com/en-us/library/azure/microsoft.windowsazure.storage.table.tablequery.aspx

Answer 2

您需要指定一个 TableQuery，这将为您提供所有实体，或者您可以指定一个 TableQuery.GenerateFilterCondition 来过滤行。

TableQuery<ServiceAlertsEntity> query = new TableQuery<ServiceAlertsEntity>();

foreach (ServiceAlertsEntity entity in table.ExecuteQuery(query))
{
    Console.WriteLine("{0}, {1}\t{2}\t{3}", entity.PartitionKey, entity.RowKey,
                        entity.Field1, entity.Field2);
}

Answer 3

如果您需要进一步控制返回的记录，您可以使用 ExecuteQuerySegmentedAsync 一次检索一页数据（大约 1,000 条记录）。

    var alerts = new List<ServiceAlertsEntity>();

    var query = new TableQuery<ServiceAlertsEntity>();
    TableContinuationToken continuationToken = null;
    do
    {
        var page = await table.ExecuteQuerySegmentedAsync(query, continuationToken);
        continuationToken = page.ContinuationToken;
        alerts.AddRange(page.Results);
    }
    while (continuationToken != null);

或者如果您需要限制结果，例如通过Partition Key，可以通过在上述代码中的查询中添加Where子句来添加过滤条件。

    var pk = "abc";
    var filterPk = TableQuery.GenerateFilterCondition(
        nameof(ServiceAlertsEntity.PartitionKey),
        QueryComparisons.Equal, pk);

    var query = new TableQuery<ServiceAlertsEntity>().Where(filterPk);

MS Azure reference

Answer 4

我使用通用 class 完成了相同的过程。使用功能应用程序我已经实现了这一点。请找到以下代码。首先我创建了一个函数应用 MyEventhubTrigger.cs

using Microsoft.ApplicationInsights;
using Microsoft.ApplicationInsights.DataContracts;
using Microsoft.Azure.WebJobs;
using Microsoft.Azure.WebJobs.ServiceBus;
using Microsoft.Extensions.Logging;
using Newtonsoft.Json;
using System;
using AzureMonitorFunctions.WebHook;



namespace MyFunctions
{
    public static class MyEventhubTrigger
    {               

        [FunctionName("MyEventhubTrigger")]       
       public static async void Run([EventHubTrigger("%EventHubName%", Connection = "EventHubConnectionString", ConsumerGroup = "devicestatuscg")] string myEventHubMessage, DateTime enqueuedTimeUtc, Int64 sequenceNumber, string offset, ILogger log)
        {           
            log.LogInformation($"C# Event Hub trigger function processed a message: {myEventHubMessage}");
            try
            {                 
                StorageTableOperation<StorageTable> tableObj = new StorageTableOperation<StorageTable>("EventhubMessages");
                Eventhubstorage Eventhubdada = tableObj.GetTableData("Eventhub", "DeviceStatus");
                if (Eventhubdada.EnqueuedTime < enqueuedTimeUtc)
                {                    
                        Eventhubdada.EnqueuedTime = enqueuedTimeUtc;
                        Eventhubdada.Offset = offset;
                        Eventhubdada.Sequence = sequenceNumber;
                        await tableObj.UpdateTableData("Eventhub", "DeviceStatus", Eventhubdada);
                    }
                }

            }
            catch (Exception ex)
            {
                log.LogInformation(ex.ToString());
            }
        }
    }
}

现在我已经在 Azure 存储帐户中创建了 table 存储。并在属性文件中添加相同的字段。这是 StorageTable.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using Microsoft.WindowsAzure.Storage.Table;

namespace MyFunctions
{
    public class StorageTable : TableEntity
    {
        public StorageTable()
        {
        }
        public StorageTable(string PKey, string RKey)
        {
            PartitionKey = PKey;
            RowKey = RKey;
        }

        public DateTime EnqueuedTime { get; set; }
        public Int64 Sequence { get; set; }
        public string Offset { get; set; }
    }
}

现在我创建了一个 class，它可以接受任何 TableEntity 属性 class 并执行以下操作 Get/insert/Update。找到以下代码 StorageTableOperation.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using Microsoft.WindowsAzure.Storage;
using Microsoft.WindowsAzure.Storage.Table;
using System.Threading.Tasks;


namespace MyFunctions
{
    public class StorageTableOperation<T> where T : ITableEntity
    {       
        internal CloudTable cloudTable;        

        public StorageTableOperation(string tableName)
        {
            string connectionString = Environment.GetEnvironmentVariable("AzureWebJobsStorage");
            CloudStorageAccount storageAccount = CloudStorageAccount.Parse(connectionString);
            CloudTableClient client = storageAccount.CreateCloudTableClient();
            cloudTable = client.GetTableReference(tableName);
        }
        public T GetTableData(string PartitionKey,string RowKey)
        {           
            TableOperation retOp = TableOperation.Retrieve<T>(PartitionKey, RowKey);
            TableResult result = cloudTable.Execute(retOp);
            T tableData = (T)result.Result;


            return tableData;
        }

        public async Task<bool> UpdateTableData(string PartitionKey, string RowKey, T tableData)
        {
            try
            {               
                TableOperation operation = TableOperation.InsertOrMerge(tableData);
                TableResult tableResult = await cloudTable.ExecuteAsync(operation);
                return true;
            }
            catch(Exception ex)
            {
                return false;
            }

        }

    }
}

从 azure table 存储中获取所有记录

Get all records from azure table storage

c#

azure

azure-table-storage