Mongdb Manipulating nested documents

1. One document is as follows

Db.posts.find ()

{    "_id": ObjectId ("5388162dfc164ee1f39be37f"),    "title":"Java Example",    "content":"This was a example for java!",    "Comments" : []}

2. Insert data into comments _id equals "5388162dfc164ee1f39be37f" in the document

Db.posts.update ({"_id": ObjectId ("5388162dfc164ee1f39be37f")},{$push:{"Comments":{"content":"Good article!","author":"Luxh"}}

Insert One more

Db.posts.update ({"_id": ObjectId ("5388162dfc164ee1f39be37f")},{$push:{"Comments":{"content":"Not bad!","author":"Chuliuxiang"}}})

The results are as follows

Db.posts.find () {"_id": ObjectId ("5388162dfc164ee1f39be37f"),    "title":"Java Example",    "content":"This was a example for java!",    "Comments" : [         {            "content":"Good article!",            "author":"Luxh"        },         {            "content":"Not bad!",            "author":"Chuliuxiang"        }    ]}

3, according to the embedded document query

1) Check out Luxh commented articles

Db.posts.find ({"Comments.author":"Luxh"}) The result is as follows: {"_id": ObjectId ("5388162dfc164ee1f39be37f"),    "title":"Java Example",    "content":"This was a example for java!",    "Comments" : [         {            "content":"Good article!",            "author":"Luxh"        },         {            "content":"Not bad!",            "author":"Chuliuxiang"        }    ]}

2) Query Luxh commented article, return the specified key

Db.posts.find ({"Comments.author":"Luxh"},{"title": 1,"content": 1}) The result is as follows: {"_id": ObjectId ("5388162dfc164ee1f39be37f"),    "title":"Java Example",    "content":"This was a example for java!"}

_ID is returned by default. Cancel to set "_id": 0

4. Modification

Modify the content of author=luxh comments to "I like it!"

Db.posts.update ({"Comments.author":"Luxh"},{$set:{"comments.$.content":"I like it!"}}) The result is as follows: {"_id": ObjectId ("5388162dfc164ee1f39be37f"),    "title":"Java Example",    "content":"This was a example for java!",    "Comments" : [         {            "content":"I like it!",            "author":"Luxh"        },         {            "content":"Not bad!",            "author":"Chuliuxiang"        }    ]}

5. Delete

Delete records from AUTHOR=LUXH in comments

Db.posts.update ({},{$pull:{"Comments":{"author":"Luxh"}}) results as follows: {"_id": ObjectId ("5388162dfc164ee1f39be37f"),    "title":"Java Example",    "content":"This was a example for java!",    "Comments" : [         {            "content":"Not bad!",            "author":"Chuliuxiang"        }    ]}