标签：c style class blog code java
1、一个文档如下
db.posts.find()
{ "_id" : ObjectId("5388162dfc164ee1f39be37f"), "title" : "Java Example", "content" : "This is a example for Java!", "comments" : [] }
2、往_id等于"5388162dfc164ee1f39be37f"的文档中的comments插入数据
db.posts.update({"_id":ObjectId("5388162dfc164ee1f39be37f")},{$push:{"comments":{"content":"Good Article!","author":"Luxh"}}
再插入一条
db.posts.update({"_id":ObjectId("5388162dfc164ee1f39be37f")},{$push:{"comments":{"content":"Not bad!","author":"Chuliuxiang"}}})
结果如下
db.posts.find() { "_id" : ObjectId("5388162dfc164ee1f39be37f"), "title" : "Java Example", "content" : "This is a example for Java!", "comments" : [ { "content" : "Good Article!", "author" : "Luxh" }, { "content" : "Not bad!", "author" : "Chuliuxiang" } ] }
3、根据内嵌文档查询
1）查询出Luxh评论过的文章
db.posts.find({"comments.author":"Luxh"})
结果如下：
{
"_id" : ObjectId("5388162dfc164ee1f39be37f"),
"title" : "Java Example",
"content" : "This is a example for Java!",
"comments" : [
{
"content" : "Good Article!",
"author" : "Luxh"
},
{
"content" : "Not bad!",
"author" : "Chuliuxiang"
}
]
}
2）查询Luxh评论过的文章，返回指定的键
db.posts.find({"comments.author":"Luxh"},{"title":1,"content":1})
结果如下：
{
"_id" : ObjectId("5388162dfc164ee1f39be37f"),
"title" : "Java Example",
"content" : "This is a example for Java!"
}
_id默认会返回。取消可设置"_id":0
4、修改
将author=Luxh评论的内容content修改为"I like it!"
db.posts.update({"comments.author":"Luxh"},{$set:{"comments.$.content":"I like it!"}})
结果如下：
{
"_id" : ObjectId("5388162dfc164ee1f39be37f"),
"title" : "Java Example",
"content" : "This is a example for Java!",
"comments" : [
{
"content" : "I like it!",
"author" : "Luxh"
},
{
"content" : "Not bad!",
"author" : "Chuliuxiang"
}
]
}
5、删除
删除comments中author=Luxh的记录
db.posts.update({},{$pull:{"comments":{"author":"Luxh"}}})
结果如下：
{
"_id" : ObjectId("5388162dfc164ee1f39be37f"),
"title" : "Java Example",
"content" : "This is a example for Java!",
"comments" : [
{
"content" : "Not bad!",
"author" : "Chuliuxiang"
}
]
}
标签：c style class blog code java
原文地址：http://www.cnblogs.com/luxh/p/3760974.html
