查询以_开头的MongoDB集合。
对于以_开头的MongoDB集合，以下是语法-
db.createCollection(‘_yourCollectionName’);
使用以下语法插入查询-
db.getCollection('_yourCollectionName').insertOne({"yourFieldName1":"yourValue1","yourFieldName2":yourValue2,............N});首先让我们创建一个包含文档的集合-
> db.createCollection('_testUnderscoreCollectionDemo');
{ "ok" : 1 }
>db.getCollection('_testUnderscoreCollectionDemo').insertOne({"StudentFirstName":"John","StudentAge":23});
{
"acknowledged" : true,
"insertedId" : ObjectId("5ccfb4a6140b992277dae0e4")
}
>db.getCollection('_testUnderscoreCollectionDemo').insertOne({"StudentFirstName":"Carol","StudentAge":21});
{
"acknowledged" : true,
"insertedId" : ObjectId("5ccfb4af140b992277dae0e5")
}以下是在find()方法的帮助下显示集合中所有文档的查询-
> db.getCollection('_testUnderscoreCollectionDemo').find().pretty();这将产生以下输出-
{
"_id" : ObjectId("5ccfb4a6140b992277dae0e4"),
"StudentFirstName" : "John",
"StudentAge" : 23
}
{
"_id" : ObjectId("5ccfb4af140b992277dae0e5"),
"StudentFirstName" : "Carol",
"StudentAge" : 21
}