Verwenden Sie die aggregierte Abfrage (Anzahl) mit dem Azure CosmosDB Java SDK

Ich bin süchtig danach, aggregierte Abfragen in CosmosDB aus dem JavaSDK zu verwenden, also werde ich das zur Kenntnis nehmen.

Wenn Sie die VALUE-Klausel in der Abfrage nicht festlegen, wird die folgende Fehlermeldung angezeigt:

java.lang.IllegalStateException: com.microsoft.azure.documentdb.DocumentClientException: Message: {"Errors":["Cross partition query only supports 'VALUE <AggreateFunc>' for aggregates."]}
Caused by: com.microsoft.azure.documentdb.DocumentClientException: Message: {"Errors":["Cross partition query only supports 'VALUE <AggreateFunc>' for aggregates."]}

Wenn setEnableCrossPartitionQuery nicht auf true gesetzt ist, tritt der folgende Fehler auf.

java.lang.IllegalStateException: com.microsoft.azure.documentdb.DocumentClientException: Cross partition query is required but disabled. Please set x-ms-documentdb-query-enablecrosspartition to true, specify x-ms-documentdb-partitionkey, or revise your query to avoid this exception.
Caused by: com.microsoft.azure.documentdb.DocumentClientException: Cross partition query is required but disabled. Please set x-ms-documentdb-query-enablecrosspartition to true, specify x-ms-documentdb-partitionkey, or revise your query to avoid this exception.

Unten ist der Java-Code.

		// Azure Cosmos DB Libraries for Java
		// https://docs.microsoft.com/ja-jp/java/api/overview/azure/cosmosdb?view=azure-java-stable

		String host = "yourhost";
		String container_id = "yourcontainer";
		String database = "yourdatabase";

		// Get key from Azure Web Console
		// read write key
		String key = "yourkey";

		String endPoint = "https://" + host + ".documents.azure.com:443";

		DocumentClient client = new DocumentClient(endPoint, key, //
				new ConnectionPolicy(), ConsistencyLevel.Session);

		String collectionLink = String.format("/dbs/%s/colls/%s", database, container_id);

		String q = String.format("SELECT VALUE count(1) FROM c");
		// IF (without 'VALUE' in query)
//		java.lang.IllegalStateException: com.microsoft.azure.documentdb.DocumentClientException: Message: {"Errors":["Cross partition query only supports 'VALUE <AggreateFunc>' for aggregates."]}
//		Caused by: com.microsoft.azure.documentdb.DocumentClientException: Message: {"Errors":["Cross partition query only supports 'VALUE <AggreateFunc>' for aggregates."]}

		FeedOptions feedOptions = new FeedOptions();
		feedOptions.setEnableCrossPartitionQuery(true);
		// IF (EnableCrossPartitionQuery = false)
//		java.lang.IllegalStateException: com.microsoft.azure.documentdb.DocumentClientException: Cross partition query is required but disabled. Please set x-ms-documentdb-query-enablecrosspartition to true, specify x-ms-documentdb-partitionkey, or revise your query to avoid this exception.
//		Caused by: com.microsoft.azure.documentdb.DocumentClientException: Cross partition query is required but disabled. Please set x-ms-documentdb-query-enablecrosspartition to true, specify x-ms-documentdb-partitionkey, or revise your query to avoid this exception.

		try {

			List<Object> results = client //
					.queryAggregateValues(collectionLink, q, feedOptions);

			System.err.println(results.get(0));

		} catch (Exception e) {
			e.printStackTrace();
		} finally {
			client.close();
		}

das ist alles.