azure Cosmos DB -删除文档

lf3rwulv  于 2023-03-03  发布在  其他
关注(0)|答案(6)|浏览(227)

如何从Cosmos DB中删除个别记录?
我可以使用SQL语法选择:

SELECT *
FROM collection1
WHERE (collection1._ts > 0)

果然返回了所有文档(类似于行?)
但是,当我尝试删除时,此操作不起作用

DELETE
FROM collection1
WHERE (collection1._ts > 0)

我该怎么做呢?

qjp7pelc

qjp7pelc1#

DocumentDB API的SQL是专门用于 * 查询 * 的,即只提供SELECT,不提供UPDATEDELETE
这些操作完全受支持,但需要REST(或SDK)调用。例如,在.net中,您将调用DeleteDocumentAsync()ReplaceDocumentAsync(),而在node.js中,这将是对deleteDocument()replaceDocument()的调用。
在您的特定场景中,您可以运行SELECT来标识要删除的文档,然后进行“delete”调用,每个文档一个(或者,为了提高效率和事务性,将要删除的文档数组传递到存储过程中)。

ig9co6j1

ig9co6j12#

最简单的方法可能是使用Azure Storage Explorer。连接后,您可以向下钻取到所选的容器,选择一个文档,然后删除它。您可以在https://gotcosmos.com/tools上找到Cosmos DB的其他工具。

bq3bfh9z

bq3bfh9z3#

另一个要考虑的选项是生存时间(TTL)。您可以为集合启用此选项,然后为文档设置过期时间。文档过期后将自动清理。

jv4diomz

jv4diomz4#

使用以下代码创建存储过程:

/**
 * A Cosmos DB stored procedure that bulk deletes documents for a given query.
 * Note: You may need to execute this stored procedure multiple times (depending whether the stored procedure 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 c._self FROM c WHERE c.founded_year = 2008"). Note: For best performance, reduce the # of properties returned per document in the query to only what's required (e.g. prefer SELECT c._self over SELECT * )
 * @returns {Object.<number, boolean>} Returns an object with the two properties:
 *   deleted - contains a count of documents deleted
 *   continuation - a boolean whether you should execute the stored procedure again (true if there are more documents to delete; false otherwise).
 */
function bulkDeleteStoredProcedure(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();
        }
    }
}

并使用您的分区密钥执行它(例如:null)和用于选择文档的查询(例如:从c中选择c._self以全部删除)。
基于Delete Documents from CosmosDB based on condition through Query Explorer

hgncfbus

hgncfbus5#

下面是一个如何使用.net Cosmos SDK V3来使用bulkDeleteStoredProcedure的示例。
由于执行界限,必须使用ContinuationFlag。

private async Task<int> ExecuteSpBulkDelete(string query, string partitionKey)
    {
        var continuationFlag = true;
        var totalDeleted = 0;
        while (continuationFlag)
        {
            StoredProcedureExecuteResponse<BulkDeleteResponse> result = await _container.Scripts.ExecuteStoredProcedureAsync<BulkDeleteResponse>(
                "spBulkDelete", // your sproc name
                new PartitionKey(partitionKey), // pk value
                new[] { sql });

            var response = result.Resource;
            continuationFlag = response.Continuation;
            var deleted = response.Deleted;
            totalDeleted += deleted;
            Console.WriteLine($"Deleted {deleted} documents ({totalDeleted} total, more: {continuationFlag}, used {result.RequestCharge}RUs)");
        }

        return totalDeleted;
    }

响应模型:

public class BulkDeleteResponse
{
    [JsonProperty("deleted")]
    public int Deleted { get; set; }

    [JsonProperty("continuation")]
    public bool Continuation { get; set; }
}
fsi0uk1n

fsi0uk1n6#

你可以使用C#通过下面的方法从cosmosdb中删除单个文档--你可以对cosmosdb容器示例使用下面的方法。
客户容器.DeleteItemAsync(ID,新分区键(“分区键的任意值”))

T-〉是容器中项目的类型。
id-〉是要删除的项目的guid。(为此您可以先使用select query从cosmsdb中获取项目)
AnyValueofPartitionKey-大多数情况下,我们使用cosmos数据库容器创建分区键,因此在这里您必须为该键提供一个值,例如-我的键是customerCity,因此我提供了“果阿”。

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