Question

我正在寻找一种使用pymongo创建mongodb 3.4+视图的方法。 mongo中的命令如下所示：

db.getCollection('parsed_tests').aggregate([{
$lookup: {
        from: "raw_tests",
        localField: "repository_path",
        foreignField: "repository_path",
        as: "raw_data"
    }
}])

我想在python中做一个初始化脚本。有没有人设法做到这一点？

Answer 1

正如sstyvane所说，您需要提供明确的数据库命令。不幸的是，他们的语法错误。

这对我有用：

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此外，如果您有从3.2或更早版本升级的Mongo实例，则可以在创建视图之前need to set the feature compatibility version to 3.4。

Answer 2

PyMongo不提供Database方法来创建视图。但是，您可以运行create命令以command方法创建视图。如果事实createView只是create命令的包装器。

db.command({
    "create": "parsed_tests_view",
    "viewOn": "parsed_tests", 
    "pipeline": pipeline
})

Answer 3

正如MongoDB documentation on views所建议的那样，专用方法createView()只是createCollection()中存在的pymongo方法的包装。

在MongoDB中，创建过程表示如下：

db.createCollection(
  "<viewName>",
  {
    "viewOn" : "<source>",
    "pipeline" : [<pipeline>],
    "collation" : { <collation> }
  }
)

在Python中，您可以通过以下代码实现相同的行为：

# Assuming `db` is your database variable
db.create_collection(
    'parsed_tests_view',
    viewOn='parsed_tests',
    pipeline=[{
        '$lookup': {
            'from': "raw_tests",
            'localField': "repository_path",
            'foreignField': "repository_path",
            'as': "raw_data"
        }
    }]
)

有关create_collection()方法in the docs of pymongo的更多信息。

如何使用pymongo创建mongo视图？

3 个答案: