Get all records from azure table storage

问题

Using this code block

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);
}

I am able to retrieve the single record with the partition and rowkey mentioned in the retrieve.

Is there a way I can get all the records that are stored in the partition of ServiceAlerts?

I have tried a wildcard (*) for the second parameter

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

but it does not return anything.

回答1:

You need to specify a TableQuery, this will give you all entities or you can specify a TableQuery.GenerateFilterCondition to filter the rows.

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);
}

回答2:

If you need further control over the records being returned, you can use ExecuteQuerySegmentedAsync to retrieve data a page (around 1,000 records) at a time.

    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);

Or if you need to restrict your results, e.g. by Partition Key, you can add a filter condition by adding a Where clause to the query in the above code.

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

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

MS Azure reference

回答3:

You're using wrong class. Use TableQuery to retrieve multiple results. https://msdn.microsoft.com/en-us/library/azure/microsoft.windowsazure.storage.table.tablequery.aspx

回答4:

I have done the same process using generic class. Using function app i have achieved this. please find the following codes. First i have created a function app 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());
            }
        }
    }
}

Now i have create table storage in azure storage account. And add the same field in a property file. which is 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; }
    }
}

Now I have created a class which can take any TableEntity property class and do the following operation Get/insert/Update. Find the following code for 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;
            }

        }

    }
}

来源：https://stackoverflow.com/questions/38748426/get-all-records-from-azure-table-storage