如何在Azure表存储中存储任意键值对? [英] How can I store arbitrary key value pairs in Azure table storage?

问题描述

背景

我正在从客户端接收CSV数据文件，这些文件包含大量不需要的数据和少量需要的数据.将来，我可能需要访问这些数据，尽管我正在归档原始数据文件，但我希望查询一些更容易的东西.我希望的解决方案不等于数据文件保持相同的格式-即客户端可以添加/删除列，并且我不希望我的实现对丢失的数据保释或无法归档其他数据.

在Azure中构建应用程序时，Azure表存储对我来说看起来是正确的-我可以读取数据文件，然后将读取的任何键/值对存储到数据存储中.

结果

我想知道如何在Azure中存储Dictionary<K, V>或Hashtable或其他一些键/值对.

解决方案

通过在从TableEntity派生的类上重写ReadEntity和WriteEntity方法，可以存储其他属性.

这是我幼稚的实现方式

public class TestEntity : TableEntity {

    public TestEntity(string a, string b) {
        PartitionKey = a;
        RowKey = b;
        DataItems = new Dictionary<string, string>();
    }

    public Dictionary<string, string> DataItems { get; set; }

    public override IDictionary<string, EntityProperty> WriteEntity(OperationContext operationContext) {
        var results = base.WriteEntity(operationContext);
        foreach (var item in DataItems) {
            results.Add("D_" + item.Key, new EntityProperty(item.Value));
        }
        return results;
    }

    public override void ReadEntity(IDictionary<string, EntityProperty> properties, OperationContext operationContext) {
        base.ReadEntity(properties, operationContext);

        DataItems = new Dictionary<string, string>();

        foreach (var item in properties) {
            if (item.Key.StartsWith("D_")) {
                string realKey = item.Key.Substring(2);
                ItemData[realKey] = item.Value.StringValue;
            }
        }
    }
}

我注意到，Azure表存储总共只能存储255个键/值对-如果考虑到PartitionKey等，则只能存储252个自定义对，因此也必须在某个地方进行处理.

Background

I am receiving CSV data files from clients that contain a large amount of data that I don't need and a small amount of data that I do. In the future I may need to access that data and although I'm archiving the original data files I was hoping for something a bit easier to query. I was hoping for a solution that didn't mean the data files stayed in the same format - i.e. the client may add/remove columns and I don't want my implementation to bail on missing data or fail to archive additional data.

As I'm building the application in Azure, Azure table storage looked correct to me - I could read the data files and then store whatever key/value pairs I read into the data store.

Upshot

I would like to know how to store a Dictionary<K, V> or Hashtable or some other key/value pairs in Azure.

解决方案

By overriding the ReadEntity and WriteEntity methods on classes derived from TableEntity, additional properties can be stored.

Here's my naive implementation

public class TestEntity : TableEntity {

    public TestEntity(string a, string b) {
        PartitionKey = a;
        RowKey = b;
        DataItems = new Dictionary<string, string>();
    }

    public Dictionary<string, string> DataItems { get; set; }

    public override IDictionary<string, EntityProperty> WriteEntity(OperationContext operationContext) {
        var results = base.WriteEntity(operationContext);
        foreach (var item in DataItems) {
            results.Add("D_" + item.Key, new EntityProperty(item.Value));
        }
        return results;
    }

    public override void ReadEntity(IDictionary<string, EntityProperty> properties, OperationContext operationContext) {
        base.ReadEntity(properties, operationContext);

        DataItems = new Dictionary<string, string>();

        foreach (var item in properties) {
            if (item.Key.StartsWith("D_")) {
                string realKey = item.Key.Substring(2);
                ItemData[realKey] = item.Value.StringValue;
            }
        }
    }
}

I've noted that Azure table storage can only store a total of 255 key/value pairs – or 252 custom ones once PartitionKey, etc. is taken into account, so this has to be handled somewhere as well.

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