如何通过c＃代码删除DocumentDB中的所有文档

Question

我正在使用Microsoft的一个名为DocumentDB的新数据库。现在我想通过ID删除文档，但我无法弄清楚，如何做到这一点。 DocumentDB中的删除操作需要自我链接，它们与我自己的ID不同。 但是我一次查询文档，然后我会得到自我链接。 通过该自我链接，我将删除该文档。

现在我想删除我馆藏中50000多个文件的所有文件。

需要获取每个文档，然后删除或使用任何简单的方法来执行相同的操作吗？

可以吗？

Answer 1

您是正确的，删除​​文档需要引用文档的_self链接。

如果您要删除集合中的所有文档，则删除和重新创建集合可能会更简单，更快捷。唯一需要注意的是，服务器端脚本（例如sprocs，udfs，triggers）也属于集合，可能也需要重新创建。

更新：我写了一个快速存储过程，在给定查询的情况下执行批量删除。这允许您在较少的网络请求中执行批量删除操作。

/**
 * A DocumentDB stored procedure that bulk deletes documents for a given query.<br/>
 * Note: You may need to execute this sproc multiple times (depending whether the sproc is able to delete every document within the execution timeout limit).
 *
 * @function
 * @param {string} query - A query that provides the documents to be deleted (e.g. "SELECT * FROM c WHERE c.founded_year = 2008")
 * @returns {Object.<number, boolean>} Returns an object with the two properties:<br/>
 *   deleted - contains a count of documents deleted<br/>
 *   continuation - a boolean whether you should execute the sproc again (true if there are more documents to delete; false otherwise).
 */
function bulkDeleteSproc(query) {
    var collection = getContext().getCollection();
    var collectionLink = collection.getSelfLink();
    var response = getContext().getResponse();
    var responseBody = {
        deleted: 0,
        continuation: true
    };

    // Validate input.
    if (!query) throw new Error("The query is undefined or null.");

    tryQueryAndDelete();

    // Recursively runs the query w/ support for continuation tokens.
    // Calls tryDelete(documents) as soon as the query returns documents.
    function tryQueryAndDelete(continuation) {
        var requestOptions = {continuation: continuation};

        var isAccepted = collection.queryDocuments(collectionLink, query, requestOptions, function (err, retrievedDocs, responseOptions) {
            if (err) throw err;

            if (retrievedDocs.length > 0) {
                // Begin deleting documents as soon as documents are returned form the query results.
                // tryDelete() resumes querying after deleting; no need to page through continuation tokens.
                //  - this is to prioritize writes over reads given timeout constraints.
                tryDelete(retrievedDocs);
            } else if (responseOptions.continuation) {
                // Else if the query came back empty, but with a continuation token; repeat the query w/ the token.
                tryQueryAndDelete(responseOptions.continuation);
            } else {
                // Else if there are no more documents and no continuation token - we are finished deleting documents.
                responseBody.continuation = false;
                response.setBody(responseBody);
            }
        });

        // If we hit execution bounds - return continuation: true.
        if (!isAccepted) {
            response.setBody(responseBody);
        }
    }

    // Recursively deletes documents passed in as an array argument.
    // Attempts to query for more on empty array.
    function tryDelete(documents) {
        if (documents.length > 0) {
            // Delete the first document in the array.
            var isAccepted = collection.deleteDocument(documents[0]._self, {}, function (err, responseOptions) {
                if (err) throw err;

                responseBody.deleted++;
                documents.shift();
                // Delete the next document in the array.
                tryDelete(documents);
            });

            // If we hit execution bounds - return continuation: true.
            if (!isAccepted) {
                response.setBody(responseBody);
            }
        } else {
            // If the document array is empty, query for more documents.
            tryQueryAndDelete();
        }
    }
}

Answer 2

这是使用C＃SDK删除文档的解决方案。下面的代码假定一个数据库和一个集合。它将迭代集合中的所有文档，并一次删除一个。要删除特定的数据库，集合或文档，请修改相应的＆＃34; CreateQuery＆＃34;包含SQL select语法的方法。例如，要选择特定数据库，

db = client.CreateDatabaseQuery().Where(o => o.Id == "MyDocDb").ToList().First();

使用单个数据库和单个集合删除DocumentDB实例中的所有文档的示例代码：

using Microsoft.Azure.Documents;
using Microsoft.Azure.Documents.Client;
using Microsoft.Azure.Documents.Linq;
using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Util
{
    class Program
    {
        private Uri _docDbUri = new Uri("https://<nameofyourdocdb>.documents.azure.com:443/");
        private string _docDbKey = "<your primary key>";

        private async Task DeleteDocsAsync()
        {
            using (var client = new DocumentClient(_docDbUri, _docDbKey))
            {
                try
                {
                    var db = client.CreateDatabaseQuery().ToList().First();
                    var coll = client.CreateDocumentCollectionQuery(db.CollectionsLink).ToList().First();
                    var docs = client.CreateDocumentQuery(coll.DocumentsLink);
                    foreach (var doc in docs)
                    {
                        await client.DeleteDocumentAsync(doc.SelfLink);
                    }
                }
                catch (Exception ex)
                {
                    Trace.WriteLine(ex);
                    throw;
                }
            }
        }



        static void Main(string[] args)
        {
            try
            {
                Program p = new Program();
                p.DeleteDocsAsync().Wait();
            }
            catch (Exception)
            {
                throw;
            }
        }
    }
}

Answer 3

这是一种删除启用了 AllowBulkExecution 的文档的方法。此方法以 100 个块为单位删除文档，因为目前 cosmos DB 一次最多仅支持 100 个操作。它获取分区键属性名称并使用反射获取其值。

public async Task BulkDeleteDocumentsAsync(IEnumerable<T> entities, string partitionKeyPropertyName)
    {
        List<Task> tasks = new List<Task>(100);
        foreach (var entity in entities)
        {
            var partitionKey = entity.GetType().GetProperty(partitionKeyPropertyName)?.GetValue(entity, null)?.ToString();
            if (partitionKey != null)
            {
                tasks.Add(DeleteDocumentAsync(entity.Id!, partitionKey)
                    .ContinueWith(itemResponse =>
                    {
                        if (!itemResponse.IsCompletedSuccessfully)
                        {
                            AggregateException innerExceptions = itemResponse.Exception!.Flatten();

                            if (innerExceptions.InnerExceptions.FirstOrDefault(innerEx => innerEx is CosmosException) is CosmosException cosmosException)
                            {
                                _logger.LogError($"Cosmos Exception deleting {entity.Id} {cosmosException.StatusCode} ({cosmosException.Message}).");
                            }
                            else
                            {
                                _logger.LogError($"Exception deleting {entity.Id} {innerExceptions.InnerExceptions.FirstOrDefault()}.");
                            }
                        }
                    }));
                if (tasks.Count == 100)
                {
                    await Task.WhenAll(tasks);
                    tasks.Clear();
                }
            }
        }
        await Task.WhenAll(tasks);
    }