原来字段：

{
    "_id" : ObjectId("5df0a28e406405edeac5001f"),
    "username" : "修改这一条，别的还存在不",
    "password" : "xxxxxxxxxxx",
    "open_id" : "123456789",
    "union_id" : "123456789",
    "telphone" : "123456789",
    "nickname" : "洛城陛下",
    "farm_id" : [ 
        "牧场id1", 
        "牧场id2"
    ],
    "is_active" : "0",
    "is_detele" : "0",
    "email" : "xxxxxx",
    "photo" : "https://www.123.png",
    "gov_addr" : "xxxxxxx",
    "auth_code" : "000",
    "register_time" : "2019-12-10",
    "update_time" : "2019-12-10"
}

 

需求一：只更新 password，telephone等字段----更新一般非嵌套字段

方法：局部更新，使用 {$set：{"username"："要修改的值"}}

python代码操作

from pymongo import MongoClient
# 这里需要说明，用_id当做查询条件，必须导入这个类，要不然报错
from bson.objectid import ObjectId

client = MongoClient(host="127.0.0.1",port=27017)
db = client["userinfo"]["user"]

ret = db.update({"_id":ObjectId("5df0a28e406405edeac5001f")},{"$set":{"username":"python修改用户名"}})

print(ret)

# 结果
{'n': 1, 'nModified': 1, 'ok': 1.0, 'updatedExisting': True}

# 要更新的值，和原来的值一样，则会返回

{'n': 1, 'nModified': 0, 'ok': 1.0, 'updatedExisting': True}

修改后的字段：

{
    "_id" : ObjectId("5df0a28e406405edeac5001f"),
    "username" : "python修改用户名",
    "password" : "xxxxxxxxxxx",
    "open_id" : "123456789",
    "union_id" : "123456789",
    "telphone" : "123456789",
    "nickname" : "洛城陛下",
    "farm_id" : [ 
        "牧场id1", 
        "牧场id2"
    ],
    "is_active" : "0",
    "is_detele" : "0",
    "email" : "xxxxx",
    "photo" : "https://www.123.png",
    "gov_addr" : "xxxxxxx",
    "auth_code" : "000",
    "register_time" : "2019-12-10",
    "update_time" : "2019-12-10"
}

需求二：更新farm_id里面的第一个元素的值为 这是数组第一个元素更新后的值

方法：局部更新：数组里面的指定的元素（而非对象）的值  使用下标进行修改

数组里面放的是元素

{"name":"zhang",

"friends":["张三","李四","王五"]}

数组里面放的是字典对象

{"name":"zhang",

"friends":[{"a":1,"b":2},{"c":3,"d":4}]}

更新前的字段：就是修改后的字段

python代码操作

from pymongo import MongoClient
from bson.objectid import ObjectId
client = MongoClient(host="127.0.0.1",port=27017)
db = client["userinfo"]["user"]

ret = db.update({"_id":ObjectId("5df0a28e406405edeac5001f")},{"$set":{"farm_id.1":"python修改后的值"}})


print(ret)

# 结果
{'n': 1, 'nModified': 1, 'ok': 1.0, 'updatedExisting': True}

 

更新后的值

{
    "_id" : ObjectId("5df0a28e406405edeac5001f"),
    "username" : "python修改用户名",
    "password" : "xxxxxxxxxxx",
    "open_id" : "123456789",
    "union_id" : "123456789",
    "telphone" : "123456789",
    "nickname" : "洛城陛下",
    "farm_id" : [ 
        "牧场id1", 
        "python修改后的值"
    ],
    "is_active" : "0",
    "is_detele" : "0",
    "email" : "xxxxxx",
    "photo" : "https://www.123.png",
    "gov_addr" : "xxxxxxx",
    "auth_code" : "000",
    "register_time" : "2019-12-10",
    "update_time" : "2019-12-10"
}

 

 假如数组里面放的是字典对象，怎么修改对象的key的值？

 新建数据格式为：

{
    "_id" : ObjectId("5df0b4bb406405edeac502a3"),
    "username" : "python修改用户名",
    "password" : "xxxxxxxxxxx",
    "farm_id" : [ 
        {
            "a" : 1
        }, 
        {
            "a" : 2
        }
    ]
}

 

需求：修改第一个数组里面的a的值为：python修改后的值  

python代码操作

from pymongo import MongoClient
from bson.objectid import ObjectId
client = MongoClient(host="127.0.0.1",port=27017)
db = client["userinfo"]["user"]

ret = db.update({"_id":ObjectId("5df0b4bb406405edeac502a3")},{"$set":{"farm_id.0.a":"python修改后的值"}})

print(ret)

# 结果
{'n': 1, 'nModified': 1, 'ok': 1.0, 'updatedExisting': True}

修改后的数据格式：

{
    "_id" : ObjectId("5df0b4bb406405edeac502a3"),
    "username" : "python修改用户名",
    "password" : "xxxxxxxxxxx",
    "farm_id" : [ 
        {
            "a" : "python修改后的值"
        }, 
        {
            "a" : 2
        }
    ]
}

但是有一个问题，假如不知道下标，但是要精准的修改数组中，指定对象的键值对的值，可以给每个对象，增加一个唯一id字段，过滤条件换成唯一id字段，而不是_id

新建数据结构

{
    "_id" : ObjectId("5df0b4bb406405edeac502a3"),
    "username" : "python修改用户名",
    "password" : "xxxxxxxxxxx",
    "farm_id" : [ 
        {
            "a" : "python修改后的值",
            "id" : "1"
        }, 
        {
            "a" : 2,
            "id" : "2"
        }
    ]
}

 

 python操作代码

from pymongo import MongoClient
from bson.objectid import ObjectId
client = MongoClient(host="127.0.0.1",port=27017)
db = client["userinfo"]["user"]

# 查询条件为 farm_id.id是为了精准定位 
ret = db.update({"farm_id.id":"1"},{"$set":{"farm_id.$.a":"python通过唯一字段，精准定位"}})
print(ret)

# 结果
{'n': 1, 'nModified': 1, 'ok': 1.0, 'updatedExisting': True}

 

修改后的字段

{
    "_id" : ObjectId("5df0b4bb406405edeac502a3"),
    "username" : "python修改用户名",
    "password" : "xxxxxxxxxxx",
    "farm_id" : [ 
        {
            "a" : "python通过唯一字段，精准定位",
            "id" : "1"
        }, 
        {
            "a" : 2,
            "id" : "2"
        }
    ]
}