Azure CosmosDB使用is_defined命令创建SQLParameter

Question

我正在尝试使用包含以下内容的查询文本创建SqlQuerySpec类：

is_defined (@param)

，我很难用@param值创建相应的SqlParameter类。它始终表示为字符串，而不是json文档路径。

示例：

Select * 
from c .... 
where is_defined("some_json_document_path")

代替：

Select * 
from c .... 
where is_defined(some_json_document_path)

Answer 1

只需稍微修改一下代码即可。

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


namespace JayGongDocumentDB.module
{
    class QueryWithSqlParam
    {
        private static readonly string endpointUrl = "https://***.documents.azure.com:443/";
        private static readonly string authorizationKey = "***";
        private static readonly string databaseId = "db";
        private static readonly string collectionId = "coll";

        private static DocumentClient client;

        public static async void QueryTest()

        {
            client = new DocumentClient(new Uri(endpointUrl), authorizationKey);
            var uri = UriFactory.CreateDocumentCollectionUri(databaseId, collectionId);

            var Parameters = new SqlParameterCollection()
                                                    {
                                                        new SqlParameter("@param", "c.test")
                                                    };

            IQueryable<Pojo> queryable = client.CreateDocumentQuery<Pojo>(
                                                uri,
                                                new SqlQuerySpec
                                                {
                                                   QueryText = "SELECT c.id,c.name,c.test FROM c WHERE is_defined(" + Parameters[0].Value + ")"
                                                });

            foreach (Pojo p in queryable)
            {
                Console.WriteLine("\nRead {0}", p);
            }
        }
    }

    class Pojo : Document
    {
        public string id { get; set; }
        public string name { get; set; }
    }

}

示例代码：

[
    {
        "id": "1",
        "name": "Jay"
    },
    {
        "id": "2",
        "name": "Bob",
        "test": []
    },
    {
        "id": "3",
        "name": "Jay"
    }
]

输出：

希望它对您有帮助。