MongoCollectionCount
MongoCollectionCount[MongoCollection[…]]
counts the number of documents in MongoCollection.
MongoCollectionCount[MongoCollection[…], query]
counts the number of documents in MongoCollection matching the query query.
更多信息和选项
- To use MongoCollectionCount, you first need to load MongoLink using Needs["MongoLink`"].
- query is an Association.
- See "Query and Projection Operators" in the MongoDB manual for available query operators.
- MongoCollectionCount corresponds to db.collection.count in the MongoDB manual.
范例
基本范例 (1)
Needs["MongoLink`"]client = MongoConnect[]Connect to a the "WolframTestCollection" collection in the "WolframTestDB" database:
coll = client["WolframTestDB"]["WolframTestCollection"]Count the number of documents in the collection:
MongoCollectionCount[coll]Count the number of documents in the collection that match the query <|"sex""female"|>:
MongoCollectionCount[coll, <|"sex" -> "female"|>]文本
Wolfram Research (2018)，MongoCollectionCount，Wolfram 语言函数，https://reference.wolfram.com/language/MongoLink/ref/MongoCollectionCount.html.
CMS
Wolfram 语言. 2018. "MongoCollectionCount." Wolfram 语言与系统参考资料中心. Wolfram Research. https://reference.wolfram.com/language/MongoLink/ref/MongoCollectionCount.html.
APA
Wolfram 语言. (2018). MongoCollectionCount. Wolfram 语言与系统参考资料中心. 追溯自 https://reference.wolfram.com/language/MongoLink/ref/MongoCollectionCount.html 年