如何使用StorageClient从Azure表中选择50至100行?
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04-10-2019 - |
题
我需要在Azure表的单个分区中选择几行,以进行以后更新。既然它们都有相同的分区键,我该如何构建查询以选择多个rowkeys?
我对RAW(电线上)查询的外观感兴趣,如果可能的话,LINQ查询也是如此。
我自己尝试了这个问题,并从此查询开始:
var results = from c in _ServiceContext.ForumThreadTable
where(
(
(c.RowKey == rk) ||
(c.RowKey == "n1q") ||
(c.RowKey == "gm1w") ||
(c.RowKey == "fm1e") ||
(c.RowKey == "zbm1r") ||
(c.RowKey == "km1te1") ||
(c.RowKey == "jm1ye1") ||
(c.RowKey == "hm1u") ||
(c.RowKey == "gm1i") ||
(c.RowKey == "fm1te1") ||
(c.RowKey == "d4m1ye1") ||
(c.RowKey == "bm1u") ||
(c.RowKey == "bm1i") ||
(c.RowKey == "bm1o") ||
(c.RowKey == "bp1p")
) &&
c.PartitionKey == pk )
select c;
我的查询看起来像这样(来自提琴手)
GET http://127.0.0.1:10002/devstoreaccount1/ForumThreadTable()?$filter=(((((((((((((((RowKey%20eq%20'0634205427898279774')%20or%20(RowKey%20eq%20'n1q'))%20or%20(RowKey%20eq%20'gm1w'))%20or%20(RowKey%20eq%20'fm1e'))%20or%20(RowKey%20eq%20'zbm1r'))%20or%20(RowKey%20eq%20'km1te1'))%20or%20(RowKey%20eq%20'jm1ye1'))%20or%20(RowKey%20eq%20'hm1u'))%20or%20(RowKey%20eq%20'gm1i'))%20or%20(RowKey%20eq%20'fm1te1'))%20or%20(RowKey%20eq%20'd4m1ye1'))%20or%20(RowKey%20eq%20'bm1u'))%20or%20(RowKey%20eq%20'bm1i'))%20or%20(RowKey%20eq%20'bm1o'))%20or%20(RowKey%20eq%20'bp1p'))%20and%20(PartitionKey%20eq%20'GUIDeec4550c-a3fd-472b-9b7d-c79fae664415') HTTP/1.1
User-Agent: Microsoft ADO.NET Data Services
DataServiceVersion: 1.0;NetFx
MaxDataServiceVersion: 2.0;NetFx
x-ms-version: 2009-09-19
x-ms-date: Mon, 20 Sep 2010 02:49:48 GMT
Authorization: SharedKeyLite devstoreaccount1:MINFtQhWqbnYhn1spDGTGvPmNmW24YNzOeqBBtOletU=
Accept: application/atom+xml,application/xml
Accept-Charset: UTF-8
Host: 127.0.0.1:10002
这是我的错误:
"<?xml version=\"1.0\" encoding=\"utf-8\" standalone=\"yes\"?>
<error xmlns=\"http://schemas.microsoft.com/ado/2007/08/dataservices/metadata\">
<code>InvalidInput</code>
<message xml:lang=\"en-US\">One of the request inputs is not valid.</message>
</error>"
我认为它可能必须在我拥有的Rowkey条件的数量上做更多的事情,而不是语法……但是我愿意尝试任何事情。
谢谢!
解决方案
那与我们在做的事情类似 lokad.cloud. 。我记得,您可以以这种方式选择多达100行,而不会出现问题。您可以检查 详细信息的源代码 并重复使用整个开源项目或您喜欢的零件。
这是语法一代的样子:
public IEnumerable<CloudEntity<T>> Get<T>(string tableName, string partitionKey, IEnumerable<string> rowKeys)
{
Enforce.That(() => tableName);
Enforce.That(() => partitionKey);
Enforce.That(!partitionKey.Contains("'"), "Incorrect char in partitionKey.");
var context = _tableStorage.GetDataServiceContext();
foreach (var slice in rowKeys.Slice(MaxEntityTransactionCount))
{
// work-around the limitation of ADO.NET that does not provide a native way
// of query a set of specified entities directly.
var builder = new StringBuilder();
builder.Append(string.Format("(PartitionKey eq '{0}') and (", HttpUtility.UrlEncode(partitionKey)));
for (int i = 0; i < slice.Length; i++)
{
// in order to avoid SQL-injection-like problems
Enforce.That(!slice[i].Contains("'"), "Incorrect char in rowKey.");
builder.Append(string.Format("(RowKey eq '{0}')", HttpUtility.UrlEncode(slice[i])));
if (i < slice.Length - 1)
{
builder.Append(" or ");
}
}
builder.Append(")");
foreach(var entity in GetInternal<T>(context, tableName, builder.ToString()))
{
yield return entity;
}
}
}
但是,请记住,该操作不会通过表存储来优化此操作,从而导致次优性能(表存储没有为此操作使用索引)。这是一个向微软报告的错误,预计将很快修复。
其他提示
您是否有此错误修复的进度更新。 Azure表存储现在使用索引执行此类查询(带有单个分区的多重行为或操作)吗?
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