DocumentDB - 删除集合

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要删除一个或多个集合，您可以从门户以及使用 .Net SDK 的代码中执行相同的操作。

步骤 1 - 转到 Azure 门户上的 DocumentDB 帐户。为了演示的目的，我添加了另外两个集合，如下面的屏幕截图所示。

步骤 2 - 要删除任何集合，您需要单击该集合。我们选择 TempCollection1。您将看到以下页面，选择“删除集合”选项。

步骤 3 - 它将显示确认消息。现在单击“是”按钮。

您将看到 TempCollection1 在仪表板上不再可用。

您还可以使用 .Net SDK 从代码中删除集合。为此，请执行以下步骤。

步骤 1 - 让我们通过指定要删除的集合的 ID 来删除集合。

这是通过 Id 查询来获取删除资源所需的 selfLink 的常见模式。

private async static Task DeleteCollection(DocumentClient client, string collectionId) {
   Console.WriteLine();
   Console.WriteLine("**** Delete Collection {0} in {1} ****", collectionId, database.Id);
	
   var query = new SqlQuerySpec {
      QueryText = "SELECT * FROM c WHERE c.id = @id",
         Parameters = new SqlParameterCollection {
         new SqlParameter {
            Name = "@id", Value = collectionId
         }
      }
   };
	
   DocumentCollection collection = client.CreateDocumentCollectionQuery(database.SelfLink,
      query).AsEnumerable().First();
		
   await client.DeleteDocumentCollectionAsync(collection.SelfLink);
   Console.WriteLine("Deleted collection {0} from database {1}", collectionId,
      database.Id);
}

在这里，我们看到了构造参数化查询的首选方法。我们没有对 collectionId 进行硬编码，因此此方法可用于删除任何集合。我们通过 Id 查询特定集合，其中 Id 参数在此 SqlParameterCollection 中定义，并分配给此 SqlQuerySpec 的参数属性。

然后，SDK 会为 DocumentDB 构建最终查询字符串，并将 collectionId 嵌入其中。

步骤 2 - 运行查询，然后使用其 SelfLink 从 CreateDocumentClient 任务中删除集合。

private static async Task CreateDocumentClient() {
   // Create a new instance of the DocumentClient 
	
   using (var client = new DocumentClient(new Uri(EndpointUrl), AuthorizationKey)) {
      database = client.CreateDatabaseQuery("SELECT * FROM c WHERE c.id =
         'myfirstdb'").AsEnumerable().First(); 
      await DeleteCollection(client, "TempCollection"); 
   } 
}

以下是 Program.cs 文件的完整实现。

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

using Microsoft.Azure.Documents;
using Microsoft.Azure.Documents.Client;
using Microsoft.Azure.Documents.Linq;

using Newtonsoft.Json;

namespace DocumentDBDemo {

   class Program {
	
      private const string EndpointUrl = "https://azuredocdbdemo.documents.azure.com:443/";
		
      private const string AuthorizationKey = "BBhjI0gxdVPdDbS4diTjdloJq7Fp4L5RO/
         StTt6UtEufDM78qM2CtBZWbyVwFPSJIm8AcfDu2O+AfV T+TYUnBQ==";
			
      private static Database database;

      static void Main(string[] args) {
         try {
            CreateDocumentClient().Wait();
         } catch (Exception e) {
            Exception baseException = e.GetBaseException();
            Console.WriteLine("Error: {0}, Message: {1}", e.Message, baseException.Message);
         }
         Console.ReadKey();
      }

      private static async Task CreateDocumentClient() {
         // Create a new instance of the DocumentClient
         using (var client = new DocumentClient(new Uri(EndpointUrl), AuthorizationKey)) {
            database = client.CreateDatabaseQuery("SELECT * FROM c WHERE c.id =
               'myfirstdb'").AsEnumerable().First();
            await DeleteCollection(client, "TempCollection");
				
            //await CreateCollection(client, "MyCollection1");
            //await CreateCollection(client, "MyCollection2", "S2");
            ////await CreateDatabase(client);
            //GetDatabases(client);
            //await DeleteDatabase(client);
            //GetDatabases(client);
         }
      }
		
      private async static Task CreateCollection(DocumentClient client,
         string collectionId, string offerType = "S1") {
			
         Console.WriteLine();
         Console.WriteLine("**** Create Collection {0} in {1} ****", collectionId,
            database.Id);
         
         var collectionDefinition = new DocumentCollection { Id = collectionId };
         var options = new RequestOptions { OfferType = offerType };
         var result = await client.CreateDocumentCollectionAsync(database.SelfLink,
            collectionDefinition, options);
				
         var collection = result.Resource; 
         
         Console.WriteLine("Created new collection"); 
         ViewCollection(collection); 
      }

      private static void ViewCollection(DocumentCollection collection) {
         Console.WriteLine("Collection ID: {0} ", collection.Id); 
         Console.WriteLine("Resource ID: {0} ", collection.ResourceId); 
         Console.WriteLine("Self Link: {0} ", collection.SelfLink); 
         Console.WriteLine("Documents Link: {0} ", collection.DocumentsLink); 
         Console.WriteLine("UDFs Link: {0} ", collection.UserDefinedFunctionsLink); 
         Console.WriteLine("StoredProcs Link: {0} ", collection.StoredProceduresLink); 
         Console.WriteLine("Triggers Link: {0} ", collection.TriggersLink); 
         Console.WriteLine("Timestamp: {0} ", collection.Timestamp); 
      }
		
      private async static Task DeleteCollection(DocumentClient client,
         string collectionId) {
			
         Console.WriteLine();
         Console.WriteLine("**** Delete Collection {0} in {1} ****", collectionId,
            database.Id);
				
         var query = new SqlQuerySpec {
            QueryText = "SELECT * FROM c WHERE c.id = @id", Parameters = new
               SqlParameterCollection {
               new SqlParameter {
                  Name = "@id", Value = collectionId
               }
            }
         };
			
         DocumentCollection collection = client.CreateDocumentCollectionQuery
            (database.SelfLink, query).AsEnumerable().First();
				
         await client.DeleteDocumentCollectionAsync(collection.SelfLink);
         Console.WriteLine("Deleted collection {0} from database {1}", collectionId,
            database.Id); 
      }
		
   } 
}

当上面的代码被编译并执行时，您将收到以下输出。

**** Delete Collection TempCollection in myfirstdb **** 
Deleted collection TempCollection from database myfirstdb