mongodb高级操作(1)-update
内容导读
互联网集市收集整理的这篇技术教程文章主要介绍了mongodb高级操作(1)-update，小编现在分享给大家，供广大互联网技能从业者学习和参考。文章包含16548字，纯文字阅读大概需要24分钟。
内容图文
前面我们已经介绍了mongodb的基本操作:mongodb基本操作
下面是介绍一些高级的增删改查操作.
1.更新文档
文档替换
最简单的方法就是文档完全替换,如下就是一个完全替换的例子,先把需要更新的文档找出来并且赋值,然后修改所赋的值,最后再进行update:
>
a1
=
db
.
test
.
findOne
()
{
"_id"
:
ObjectId
(
"5738785d132e1e47e535a177"
),
"x"
:
3.14
,
"y"
:
5.5
}
>
a1
{
"_id"
:
ObjectId
(
"5738785d132e1e47e535a177"
),
"x"
:
3.14
,
"y"
:
5.5
}
>
delete
a1
.
x
true
>
a1
{
"_id"
:
ObjectId
(
"5738785d132e1e47e535a177"
),
"y"
:
5.5
}
>
a1
.
content
={
name
:
‘job‘
,
age
:
11
}
{
"name"
:
"job"
,
"age"
:
11
}
>
a1
{
"_id"
:
ObjectId
(
"5738785d132e1e47e535a177"
),
"y"
:
5.5
,
"content"
:
{
"name"
:
"job"
,
"age"
:
11
}
}
>
db
.
test
.
update
({
"_id"
:
ObjectId
(
"5738785d132e1e47e535a177"
)},
a1
)
WriteResult
({
"nMatched"
:
1
,
"nUpserted"
:
0
,
"nModified"
:
1
})
使用修改器
通常文档只会有一部分需要更新,可以使用原子性的更新修改器对指定文档中的某些键进行更新
"$set"修改器
"$set"修改器用来指定一个字段的值,如果这个字段不存在则创建它,例如先给test表添加一个phone属性:
>
db
.
test
.
find
()
{
"_id"
:
ObjectId
(
"573957c55f74882a9bfa2d9e"
),
"name"
:
"brent"
,
"age"
:
30
,
"email"
:
"xxxx@qq.com"
}
>
>
db
.
test
.
update
({
"_id"
:
ObjectId
(
"573957c55f74882a9bfa2d9e"
)},{
"$set"
:{
phone
:
666
}})
WriteResult
({
"nMatched"
:
1
,
"nUpserted"
:
0
,
"nModified"
:
1
})
>
>
db
.
test
.
find
()
{
"_id"
:
ObjectId
(
"573957c55f74882a9bfa2d9e"
),
"name"
:
"brent"
,
"age"
:
30
,
"email"
:
"xxxx@qq.com"
,
"phone"
:
666
}
然后用修改器再将phone该为888
>
db
.
test
.
update
({
"_id"
:
ObjectId
(
"573957c55f74882a9bfa2d9e"
)},{
"$set"
:{
phone
:
888
}})
WriteResult
({
"nMatched"
:
1
,
"nUpserted"
:
0
,
"nModified"
:
1
})
>
db
.
test
.
find
()
{
"_id"
:
ObjectId
(
"573957c55f74882a9bfa2d9e"
),
"name"
:
"brent"
,
"age"
:
30
,
"email"
:
"xxxx@qq.com"
,
"phone"
:
888
}
使用"$set"修改器还可以修改字段的属性,例如可以把phone改成一个数组,还可以用"$unset"将键完全删除:
>
db
.
test
.
update
({
"_id"
:
ObjectId
(
"573957c55f74882a9bfa2d9e"
)},{
"$unset"
:{
phone
:
888
}})
WriteResult
({
"nMatched"
:
1
,
"nUpserted"
:
0
,
"nModified"
:
1
})
>
db
.
test
.
find
()
{
"_id"
:
ObjectId
(
"573957c55f74882a9bfa2d9e"
),
"name"
:
"brent"
,
"age"
:
30
,
"email"
:
"xxxx@qq.com"
}
使用"$set"修改内嵌文档:
>
db
.
test
.
find
()
{
"_id"
:
ObjectId
(
"573957c55f74882a9bfa2d9e"
),
"name"
:
"brent"
,
"age"
:
30
,
"email"
:
"xxxx@qq.com"
}
{
"_id"
:
ObjectId
(
"57395fa85f74882a9bfa2d9f"
),
"id"
:
{
"phone"
:
888
,
"address"
:
"abc"
}
}
>
>
db
.
test
.
update
({
"_id"
:
ObjectId
(
"57395fa85f74882a9bfa2d9f"
)},{
"$set"
:{
"id.phone"
:
666
}})
WriteResult
({
"nMatched"
:
1
,
"nUpserted"
:
0
,
"nModified"
:
1
})
>
>
db
.
test
.
find
()
{
"_id"
:
ObjectId
(
"573957c55f74882a9bfa2d9e"
),
"name"
:
"brent"
,
"age"
:
30
,
"email"
:
"xxxx@qq.com"
}
{
"_id"
:
ObjectId
(
"57395fa85f74882a9bfa2d9f"
),
"id"
:
{
"phone"
:
666
,
"address"
:
"abc"
}
}
"$inc"增加和减少
"$inc"修改器用来增加和减少已有键的值,只能用于整形,长整形或者双精度浮点型的值,用在其它类型的值上面会报错.对于不存在的键,像"$set"那样也会自动创建相应的键,并且值为给定的值
例如我们用"$inc"修改器给age值+1,原来是30,现在变成了31
>
db
.
test
.
find
()
{
"_id"
:
ObjectId
(
"573957c55f74882a9bfa2d9e"
),
"name"
:
"brent"
,
"age"
:
30
,
"email"
:
"xxxx@qq.com"
}
{
"_id"
:
ObjectId
(
"57395fa85f74882a9bfa2d9f"
),
"id"
:
{
"phone"
:
666
,
"address"
:
"abc"
}
}
>
db
.
test
.
update
({
"_id"
:
ObjectId
(
"573957c55f74882a9bfa2d9e"
)},{
"$inc"
:{
age
:
1
}})
WriteResult
({
"nMatched"
:
1
,
"nUpserted"
:
0
,
"nModified"
:
1
})
>
db
.
test
.
find
()
{
"_id"
:
ObjectId
(
"573957c55f74882a9bfa2d9e"
),
"name"
:
"brent"
,
"age"
:
31
,
"email"
:
"xxxx@qq.com"
}
{
"_id"
:
ObjectId
(
"57395fa85f74882a9bfa2d9f"
),
"id"
:
{
"phone"
:
666
,
"address"
:
"abc"
}
}
如果要减少,则将age:1里的1改成-1
"$push"数组修改器-添加元素
如果数组已经存在,那么"$push"会向已有的数组末尾添加一个元素,如果没有就创建一个新的数组 ,下面这个例子会创建一个表示comments的数组:
>
db
.
test
.
find
()
{
"_id"
:
ObjectId
(
"573957c55f74882a9bfa2d9e"
),
"name"
:
"brent"
,
"age"
:
30
,
"email"
:
"xxxx@qq.com"
,
"phone"
:
888
}
{
"_id"
:
ObjectId
(
"57395fa85f74882a9bfa2d9f"
),
"id"
:
{
"phone"
:
666
,
"address"
:
"abc"
}
}
>
db
.
test
.
update
({
"_id"
:
ObjectId
(
"573957c55f74882a9bfa2d9e"
)},{
"$push"
:{
comments
:
...
{
name
:
"jack"
,
content
:
"good"
}
...
}})
WriteResult
({
"nMatched"
:
1
,
"nUpserted"
:
0
,
"nModified"
:
1
})
>
db
.
test
.
find
()
{
"_id"
:
ObjectId
(
"573957c55f74882a9bfa2d9e"
),
"name"
:
"brent"
,
"age"
:
30
,
"email"
:
"xxxx@qq.com"
,
"phone"
:
888
,
"comments"
:
[
{
"name"
:
"jack"
,
"content"
:
"good"
}
]
}
{
"_id"
:
ObjectId
(
"57395fa85f74882a9bfa2d9f"
),
"id"
:
{
"phone"
:
666
,
"address"
:
"abc"
}
}
继续给comments添加值:
>
db
.
test
.
update
({
"_id"
:
ObjectId
(
"573957c55f74882a9bfa2d9e"
)},{
"$push"
:{
comments
:
{
name
:
"tom"
,
content
:
"very good"
}
}})
WriteResult
({
"nMatched"
:
1
,
"nUpserted"
:
0
,
"nModified"
:
1
})
>
db
.
test
.
find
()
{
"_id"
:
ObjectId
(
"573957c55f74882a9bfa2d9e"
),
"name"
:
"brent"
,
"age"
:
30
,
"email"
:
"xxxx@qq.com"
,
"phone"
:
888
,
"comments"
:
[
{
"name"
:
"jack"
,
"content"
:
"good"
},
{
"name"
:
"tom"
,
"content"
:
"very good"
}
]
}
{
"_id"
:
ObjectId
(
"57395fa85f74882a9bfa2d9f"
),
"id"
:
{
"phone"
:
666
,
"address"
:
"abc"
}
}
还可以将"$push"和"$each"一起使用,一次添加多个值
>
db
.
test
.
update
({
"_id"
:
ObjectId
(
"573957c55f74882a9bfa2d9e"
)},{
"$push"
:{
comments
:
{
"$each"
:[
"a"
,
"b"
,
"c"
]}}})
WriteResult
({
"nMatched"
:
1
,
"nUpserted"
:
0
,
"nModified"
:
1
})
>
>
>
db
.
test
.
findOne
()
{
"_id"
:
ObjectId
(
"573957c55f74882a9bfa2d9e"
),
"name"
:
"brent"
,
"age"
:
30
,
"email"
:
"xxxx@qq.com"
,
"phone"
:
888
,
"comments"
:
[
{
"name"
:
"jack"
,
"content"
:
"good"
},
{
"name"
:
"tom"
,
"content"
:
"very good"
},
"a"
,
"b"
,
"c"
]
}
还可以将"$slice"和"$push"组合在一起使用,这样就保证数组不会超出设定好的最大长度,这实际上得到了一个最多包含N个元素的数组:
>
db
.
test
.
update
({
"_id"
:
ObjectId
(
"573957c55f74882a9bfa2d9e"
)},{
"$push"
:{
comments
:
{
"$each"
:[
"a"
,
"b"
,
"c"
],
"$slice"
:-
10
}}})
这个例子会限制数组只包含最后加入的10个元素,"$slice"的值必须是负整数.
还可以使用"$sort"对数组中的对象进行排序,注意"$slice"必须和"$each"配合使用.
"$ne"和"$addToSet"将数组作为数据集使用
当将数组作为数据集使用进行的更新的时候,要保证数组内的元素不能重复,当update的数据重复即不做,如果不重复则进行更新,可以使用"$ne",也可以使用"$addToSet"
使用"$ne"的方法:
>
db
.
test
.
update
({
"comments"
:{
"$ne"
:
"jack"
}},{
"$push"
:{
"comments"
:
"jack"
}})
WriteResult
({
"nMatched"
:
1
,
"nUpserted"
:
0
,
"nModified"
:
1
})
>
db
.
test
.
findOne
()
{
"_id"
:
ObjectId
(
"573957c55f74882a9bfa2d9e"
),
"name"
:
"brent"
,
"age"
:
30
,
"email"
:
"xxxx@qq.com"
,
"phone"
:
888
,
"comments"
:
[
{
"name"
:
"jack"
,
"content"
:
"good"
},
{
"name"
:
"tom"
,
"content"
:
"very good"
},
"a"
,
"b"
,
"c"
,
"a"
,
"b"
,
"c"
,
"jack"
]
感觉ne就是not equal的意思
其实按照我的理解上面那句话就是当comment这个数组内的元素ne(不等于)jack的时候,使用push在comment里将jack这个元素添加到commnts数组中.
使用"$addToSet"的方法:
>
db
.
test
.
update
({
"_id"
:
ObjectId
(
"573957c55f74882a9bfa2d9e"
)},{
"$addToSet"
:{
"comments"
:
"andy"
}})
WriteResult
({
"nMatched"
:
1
,
"nUpserted"
:
0
,
"nModified"
:
1
})
>
>
db
.
test
.
findOne
()
{
"_id"
:
ObjectId
(
"573957c55f74882a9bfa2d9e"
),
"name"
:
"brent"
,
"age"
:
30
,
"email"
:
"xxxx@qq.com"
,
"phone"
:
888
,
"comments"
:
[
{
"name"
:
"jack"
,
"content"
:
"good"
},
{
"name"
:
"tom"
,
"content"
:
"very good"
},
"a"
,
"b"
,
"c"
,
"a"
,
"b"
,
"c"
,
"jack"
,
"andy"
]
}
个人觉得"$addToset"的方法更好用一点,而且格式和上面介绍的集中类似.而且"$addToset"可以和"$each"组合起来进行批量的添加
>
db
.
test
.
update
({
"_id"
:
ObjectId
(
"573957c55f74882a9bfa2d9e"
)},{
"$addToSet"
:{
"comments"
:{
"$each"
:[
"andy"
,
"lily"
,
"lucy"
]}}})
WriteResult
({
"nMatched"
:
1
,
"nUpserted"
:
0
,
"nModified"
:
1
})
>
db
.
test
.
findOne
()
{
"_id"
:
ObjectId
(
"573957c55f74882a9bfa2d9e"
),
"name"
:
"brent"
,
"age"
:
30
,
"email"
:
"xxxx@qq.com"
,
"phone"
:
888
,
"comments"
:
[
{
"name"
:
"jack"
,
"content"
:
"good"
},
{
"name"
:
"tom"
,
"content"
:
"very good"
},
"a"
,
"b"
,
"c"
,
"a"
,
"b"
,
"c"
,
"jack"
,
"andy"
,
"lily"
,
"lucy"
]
}
"$pop"和"$pull"删除数组元素
可以使用"$pop"方法将数组进行出列操作{"$pop:{"key":1}}从数组key的末尾元素开始出列,key为-1从头部开始出列,下面这个例子将lucy删除掉了:
>
db
.
test
.
update
({
"_id"
:
ObjectId
(
"573957c55f74882a9bfa2d9e"
)},{
"$pop"
:{
"comments"
:
1
}})
WriteResult
({
"nMatched"
:
1
,
"nUpserted"
:
0
,
"nModified"
:
1
})
>
db
.
test
.
findOne
()
{
"_id"
:
ObjectId
(
"573957c55f74882a9bfa2d9e"
),
"name"
:
"brent"
,
"age"
:
30
,
"email"
:
"xxxx@qq.com"
,
"phone"
:
888
,
"comments"
:
[
{
"name"
:
"jack"
,
"content"
:
"good"
},
{
"name"
:
"tom"
,
"content"
:
"very good"
},
"a"
,
"b"
,
"c"
,
"a"
,
"b"
,
"c"
,
"jack"
,
"andy"
,
"lily"
]
}
如果不是从开头或者末尾删除,可以使用"$pull",它会删除所有匹配的文档,如下删除了所有的a:
>
db
.
test
.
update
({
"_id"
:
ObjectId
(
"573957c55f74882a9bfa2d9e"
)},{
"$pull"
:{
"comments"
:
"a"
}})
WriteResult
({
"nMatched"
:
1
,
"nUpserted"
:
0
,
"nModified"
:
1
})
>
db
.
test
.
findOne
()
{
"_id"
:
ObjectId
(
"573957c55f74882a9bfa2d9e"
),
"name"
:
"brent"
,
"age"
:
30
,
"email"
:
"xxxx@qq.com"
,
"phone"
:
888
,
"comments"
:
[
{
"name"
:
"jack"
,
"content"
:
"good"
},
{
"name"
:
"tom"
,
"content"
:
"very good"
},
"b"
,
"c"
,
"b"
,
"c"
,
"jack"
,
"andy"
,
"lily"
]
}
$基于位置的数组修改
如果数组有多个值,而我们只想对其中一部分进行操作,有两种方法操作数组中的值:通过位置或者定位操作符$
数组下标都是以0开始的,可以将下标直接作为键的选择元素,下面这个例子给comments这个数组的第一个元素添加一个num:1的元素
>
db
.
test
.
findOne
()
{
"_id"
:
ObjectId
(
"573957c55f74882a9bfa2d9e"
),
"name"
:
"brent"
,
"age"
:
30
,
"email"
:
"xxxx@qq.com"
,
"phone"
:
888
,
"comments"
:
[
{
"name"
:
"tom"
,
"content"
:
"very good"
},
"jack"
,
"andy"
,
"lily"
]
}
>
db
.
test
.
update
({
"_id"
:
ObjectId
(
"573957c55f74882a9bfa2d9e"
)},{
"$set"
:{
"comments.0.num"
:
1
}})
WriteResult
({
"nMatched"
:
1
,
"nUpserted"
:
0
,
"nModified"
:
1
})
>
>
>
db
.
test
.
findOne
()
{
"_id"
:
ObjectId
(
"573957c55f74882a9bfa2d9e"
),
"name"
:
"brent"
,
"age"
:
30
,
"email"
:
"xxxx@qq.com"
,
"phone"
:
888
,
"comments"
:
[
{
"name"
:
"tom"
,
"content"
:
"very good"
,
"num"
:
1
},
"jack"
,
"andy"
,
"lily"
]
}
再对这个num加上1:
>
db
.
test
.
update
({
"_id"
:
ObjectId
(
"573957c55f74882a9bfa2d9e"
)},{
"$inc"
:{
"comments.0.num"
:
1
}})
WriteResult
({
"nMatched"
:
1
,
"nUpserted"
:
0
,
"nModified"
:
1
})
>
db
.
test
.
findOne
()
{
"_id"
:
ObjectId
(
"573957c55f74882a9bfa2d9e"
),
"name"
:
"brent"
,
"age"
:
30
,
"email"
:
"xxxx@qq.com"
,
"phone"
:
888
,
"comments"
:
[
{
"name"
:
"tom"
,
"content"
:
"very good"
,
"num"
:
2
},
"jack"
,
"andy"
,
"lily"
]
}
这种方法的弊端是需要先查询出数据,然后根据数据你才知道需要修改的数组的下标.为了客服这个困难mongodb提供了定位操作符$,用来定位匹配的元素,定位符只匹配第一个的元素,例如我们把上面的tom改成jack:
>
db
.
test
.
update
({
"comments.name"
:
"tom"
},{
"$set"
:{
"comments.$.name"
:
"jack"
}})
WriteResult
({
"nMatched"
:
1
,
"nUpserted"
:
0
,
"nModified"
:
1
})
>
db
.
test
.
findOne
()
{
"_id"
:
ObjectId
(
"573957c55f74882a9bfa2d9e"
),
"name"
:
"brent"
,
"age"
:
30
,
"email"
:
"xxxx@qq.com"
,
"phone"
:
888
,
"comments"
:
[
{
"name"
:
"jack"
,
"content"
:
"very good"
,
"num"
:
2
},
"jack"
,
"andy"
,
"lily"
]
}
upsert
upsert是一种特殊的更新,要是没有找到符合条件的更新那么就创建一个新的文档,如果找到就正常更新.
update的第三个参数即控制update是普通的update还是upsert,默认为false,即普通的update,如果设置成true,则为upsert
下面的这个例子查找name为bob的,如果有就给age加1,如果没有则创建name为bob,并且设置age为1,使用upsert实现:
>
db
.
test
.
find
()
{
"_id"
:
ObjectId
(
"573c858c323f7f2e2ccb0e17"
),
"name"
:
"brent"
,
"age"
:
28
}
>
db
.
test
.
update
({
"name"
:
"bob"
},{
"$inc"
:{
"age"
:
1
}},
true
)
WriteResult
({
"nMatched"
:
0
,
"nUpserted"
:
1
,
"nModified"
:
0
,
"_id"
:
ObjectId
(
"573c86d3017c5eb7d08aed6d"
)
})
>
db
.
test
.
find
()
{
"_id"
:
ObjectId
(
"573c858c323f7f2e2ccb0e17"
),
"name"
:
"brent"
,
"age"
:
28
}
{
"_id"
:
ObjectId
(
"573c86d3017c5eb7d08aed6d"
),
"name"
:
"bob"
,
"age"
:
1
}
>
有的时候需要创建文档的同时创建字段并为他赋值,但是在之后的更新中这个字段的值不再改变,这就是"$setOnInsert"的作用.
"$setOnInsert"只会在文档插入的时候设置字段的值.
下面这个例子第一次使用upsert,因为没有name为tom的所以插入age为10,第二次再使用upsert想设置tom的age为20,因为使用
"$setOnInsert"而且tom已经存在那么就不会再更新了
>
db
.
test
.
find
()
{
"_id"
:
ObjectId
(
"573c858c323f7f2e2ccb0e17"
),
"name"
:
"brent"
,
"age"
:
28
}
{
"_id"
:
ObjectId
(
"573c86d3017c5eb7d08aed6d"
),
"name"
:
"bob"
,
"age"
:
1
}
>
db
.
test
.
update
({
"name"
:
"tom"
},{
"$setOnInsert"
:{
"age"
:
10
}},
true
)
WriteResult
({
"nMatched"
:
0
,
"nUpserted"
:
1
,
"nModified"
:
0
,
"_id"
:
ObjectId
(
"573c88fe017c5eb7d08aed6e"
)
})
>
db
.
test
.
find
()
{
"_id"
:
ObjectId
(
"573c858c323f7f2e2ccb0e17"
),
"name"
:
"brent"
,
"age"
:
28
}
{
"_id"
:
ObjectId
(
"573c86d3017c5eb7d08aed6d"
),
"name"
:
"bob"
,
"age"
:
1
}
{
"_id"
:
ObjectId
(
"573c88fe017c5eb7d08aed6e"
),
"name"
:
"tom"
,
"age"
:
10
}
>
db
.
test
.
update
({
"name"
:
"tom"
},{
"$setOnInsert"
:{
"age"
:
20
}},
true
)
WriteResult
({
"nMatched"
:
1
,
"nUpserted"
:
0
,
"nModified"
:
0
})
>
db
.
test
.
find
()
{
"_id"
:
ObjectId
(
"573c858c323f7f2e2ccb0e17"
),
"name"
:
"brent"
,
"age"
:
28
}
{
"_id"
:
ObjectId
(
"573c86d3017c5eb7d08aed6d"
),
"name"
:
"bob"
,
"age"
:
1
}
{
"_id"
:
ObjectId
(
"573c88fe017c5eb7d08aed6e"
),
"name"
:
"tom"
,
"age"
:
10
}
save shell帮助程序
save是一个shell函数,如果文档不存在,它会自动创建文档,如果存在它就更新这个文档,他只有一个参数:文档.
如果这个文档中含有_id则会调用upsert,如果没有则调用insert
>
var
a
=
db
.
test
.
findOne
()
>
a
{
"_id"
:
ObjectId
(
"573c858c323f7f2e2ccb0e17"
),
"name"
:
"brent"
,
"age"
:
28
}
>
a
.
age
=
40
40
>
a
{
"_id"
:
ObjectId
(
"573c858c323f7f2e2ccb0e17"
),
"name"
:
"brent"
,
"age"
:
40
}
>
db
.
test
.
save
(
a
)
WriteResult
({
"nMatched"
:
1
,
"nUpserted"
:
0
,
"nModified"
:
1
})
>
db
.
test
.
find
()
{
"_id"
:
ObjectId
(
"573c858c323f7f2e2ccb0e17"
),
"name"
:
"brent"
,
"age"
:
40
}
{
"_id"
:
ObjectId
(
"573c86d3017c5eb7d08aed6d"
),
"name"
:
"bob"
,
"age"
:
1
}
{
"_id"
:
ObjectId
(
"573c88fe017c5eb7d08aed6e"
),
"name"
:
"tom"
,
"age"
:
10
}
更新多个文档
mongodb默认情况下如果匹配到了多个文档,在更新的时候默认只会更新第一个文档,其他文档不发生变化,如果要更新所有的文档则需要将update的第四个参数设置为true,默认为false
例如下面的例子,第一次更新不设置第四个参数,返回只update了一条数据,第二次设置第四个参数为true,则会匹配更新所有数据:
>
db
.
test
.
find
({
"name"
:
"brent"
}
)
{
"_id"
:
ObjectId
(
"573c858c323f7f2e2ccb0e17"
),
"name"
:
"brent"
,
"age"
:
40
}
{
"_id"
:
ObjectId
(
"573c8bd3323f7f2e2ccb0e18"
),
"name"
:
"brent"
,
"age"
:
28
}
>
db
.
test
.
update
({
"name"
:
"brent"
},{
"$inc"
:{
"age"
:
1
}})
WriteResult
({
"nMatched"
:
1
,
"nUpserted"
:
0
,
"nModified"
:
1
})
>
db
.
test
.
update
({
"name"
:
"brent"
},{
"$inc"
:{
"age"
:
1
}},
false
,
true
)
WriteResult
({
"nMatched"
:
2
,
"nUpserted"
:
0
,
"nModified"
:
2
})
>
db
.
test
.
find
({
"name"
:
"brent"
}
)
{
"_id"
:
ObjectId
(
"573c858c323f7f2e2ccb0e17"
),
"name"
:
"brent"
,
"age"
:
42
}
{
"_id"
:
ObjectId
(
"573c8bd3323f7f2e2ccb0e18"
),
"name"
:
"brent"
,
"age"
:
29
}
>
如果想知道多文档更新到底更新了多少文档,可以运行getLastError命令,(可以理解为返回最后一次操作的相关信息),建n的值就是被更新的文档的数量:
>
db
.
test
.
update
({
"name"
:
"brent"
},{
"$inc"
:{
"age"
:
1
}},
false
,
true
)
WriteResult
({
"nMatched"
:
2
,
"nUpserted"
:
0
,
"nModified"
:
2
})
>
db
.
runCommand
({
getLastError
:
1
})
{
"connectionId"
:
1
,
"updatedExisting"
:
true
,
"n"
:
2
,
"syncMillis"
:
0
,
"writtenTo"
:
null
,
"err"
:
null
,
"ok"
:
1
}
返回被更新的文档
getLastError只能获得更新的相关信息,并不能返回被更新的文档,可以通过findAndModify命令得到被更新的文档.
下面这个例子,查询status为ready的文档,进行处理,处理完成之后将ready改成done,先来看看当前的数据:
>
db
.
test
.
find
()
{
"_id"
:
ObjectId
(
"573c858c323f7f2e2ccb0e17"
),
"name"
:
"brent"
,
"age"
:
43
,
"status"
:
"done"
}
{
"_id"
:
ObjectId
(
"573c86d3017c5eb7d08aed6d"
),
"name"
:
"bob"
,
"age"
:
1
,
"status"
:
"ready"
}
{
"_id"
:
ObjectId
(
"573c88fe017c5eb7d08aed6e"
),
"name"
:
"tom"
,
"age"
:
10
,
"status"
:
"ready"
}
{
"_id"
:
ObjectId
(
"573c8bd3323f7f2e2ccb0e18"
),
"name"
:
"brent"
,
"age"
:
30
,
"status"
:
"done"
}
下面这条语句是将集合test中status为ready的一个文档修改为running:
>
ps
=
db
.
runCommand
({
"findAndModify"
:
"test"
, #集合名
...
"query"
:{
"status"
:
"ready"
},
...
"sort"
:{
"age"
:-
1
},
...
"update"
:{
"$set"
:{
"status"
:
"running"
}}}).
value
然后你可以对这条数据进行一些处理
Process(ps).......
最后处理完成之后,将这个文档status设置为done
>
db
.
test
.
update
({
"_id"
:
ps
.
_id
},{
"$set"
:{
"status"
:
"done"
}})
WriteResult
({
"nMatched"
:
1
,
"nUpserted"
:
0
,
"nModified"
:
1
})
>
db
.
test
.
find
()
{
"_id"
:
ObjectId
(
"573c858c323f7f2e2ccb0e17"
),
"name"
:
"brent"
,
"age"
:
43
,
"status"
:
"done"
}
{
"_id"
:
ObjectId
(
"573c86d3017c5eb7d08aed6d"
),
"name"
:
"bob"
,
"age"
:
1
,
"status"
:
"ready"
}
{
"_id"
:
ObjectId
(
"573c88fe017c5eb7d08aed6e"
),
"name"
:
"tom"
,
"age"
:
10
,
"status"
:
"done"
}
{
"_id"
:
ObjectId
(
"573c8bd3323f7f2e2ccb0e18"
),
"name"
:
"brent"
,
"age"
:
30
,
"status"
:
"done"
}
这样就提供了一个很好的操作队列和原子性的方法,而且你可以写一个循环把集合中的文档类似于放到一个队列中处理.
findAndModify有很多参数可以使用,例如上面我们使用到了query,sort,update
findAndModify
字符串集合名
query
查询文档,用于检索文档的条件
sort
排序结果集,我们处理的时候可能需要按照某个顺序来进行处理
update
修改器文档,用于对匹配的文件进行修改
remove
布尔类型,表示是否删除文档(remove和update必须指定中的一个)
remove的语法如下:
.....
"remove"
:true
}).value
new
布尔类型,表示返回更新前的文档还是更新后的,默认返回更新前的文档
fields
文档中需要返回的字段(可选)
upsert
布尔类型,当是true的时候表示这是一个upsert,默认为false
update和remove必须有一个,而且只能有一个,如果没有匹配的文档,这个命令会返回一个错误
原文：http://blog.csdn.net/su377486/article/details/51449688
内容总结
以上是互联网集市为您收集整理的mongodb高级操作(1)-update全部内容，希望文章能够帮你解决mongodb高级操作(1)-update所遇到的程序开发问题。 如果觉得互联网集市技术教程内容还不错，欢迎将互联网集市网站推荐给程序员好友。
内容备注
版权声明：本文内容由互联网用户自发贡献，该文观点与技术仅代表作者本人。本站仅提供信息存储空间服务，不拥有所有权，不承担相关法律责任。如发现本站有涉嫌侵权/违法违规的内容， 请发送邮件至 gblab@vip.qq.com 举报，一经查实，本站将立刻删除。
内容手机端
扫描二维码推送至手机访问。
来源：【匿名】