0
样品采集结构MongoDB的位置操作:嵌套数组
{
"_id" : ObjectId("57cfd62001ca2dd672cfebb1"),
"name" : "Category",
"parent" : ObjectId("57cfd5d101ca2dd672cfebb0"),
"posts" : [
{
"name" : "Post",
"author" : ObjectId("57cfd09401ca2dd672cfebac"),
"content" : "Some content.",
"comments" : [
{
"author" : ObjectId("57cfd09401ca2dd672cfebab"),
"content" : "First comment",
"rating" : 2
},
{
"author" : ObjectId("57cfd09401ca2dd672cfebac"),
"content" : "Second comment",
"rating" : 5
}
]
}
]
}
我想选择所有comments
其author
是ObjectId("57cfd09401ca2dd672cfebab")
。
此查询工作,
db.categories.find({ 'posts.comments.author':ObjectId("57cfd09401ca2dd672cfebab") })
,但我想只有首先匹配与位置运算符注释返回。像这样的东西不起作用。 MongoDB是否支持嵌套数组的位置操作符?
db.categories.find({ 'posts.comments.author': ObjectId("57cfd09401ca2dd672cfebab") },
{ 'posts.comments.$': 1 })