mongo-update

可以根据条件来更新指定的文档，但要注意查询条件的唯一性：

> db.tianyc04.remove()

> db.tianyc04.insert({name:'tyc',age:20})

> db.tianyc04.insert({name:'tyc',age:30})

> db.tianyc04.insert({name:'tyc',age:32})

> db.tianyc04.find()

{ "_id" : ObjectId("510c83ad13d7e50c2281b048"), "name" : "tyc", "age" : 20 }

{ "_id" : ObjectId("510c83b113d7e50c2281b049"), "name" : "tyc", "age" : 30 }

{ "_id" : ObjectId("510c83b313d7e50c2281b04a"), "name" : "tyc", "age" : 32 }

> x=db.tianyc04.findOne()

{ "_id" : ObjectId("510c83ad13d7e50c2281b048"), "name" : "tyc", "age" : 20 }

> x.age++

20

> x

{ "_id" : ObjectId("510c83ad13d7e50c2281b048"), "name" : "tyc", "age" : 21 }

#按照name条件更新，将会更新所有记录。但x中已经包含了_id字段，这样会产生主键重复，所以mongo只会更新第一个。

> db.tianyc04.update({name:'tyc'}, x)

> db.tianyc04.find()

{ "_id" : ObjectId("510c83ad13d7e50c2281b048"), "name" : "tyc", "age" : 21 }

{ "_id" : ObjectId("510c83b113d7e50c2281b049"), "name" : "tyc", "age" : 30 }

{ "_id" : ObjectId("510c83b313d7e50c2281b04a"), "name" : "tyc", "age" : 32 }

#如果我更新第二条数据，会怎么样呢：

> x=db.tianyc04.findOne({age:30})

{ "_id" : ObjectId("510c83b113d7e50c2281b049"), "name" : "tyc", "age" : 30 }

> x.age++

30

> x

{ "_id" : ObjectId("510c83b113d7e50c2281b049"), "name" : "tyc", "age" : 31 }

> db.tianyc04.update({name:'tyc'},x)

> db.tianyc04.find()

{ "_id" : ObjectId("510c83ad13d7e50c2281b048"), "name" : "tyc", "age" : 21 }

{ "_id" : ObjectId("510c83b113d7e50c2281b049"), "name" : "tyc", "age" : 30 }

{ "_id" : ObjectId("510c83b313d7e50c2281b04a"), "name" : "tyc", "age" : 32 }

> db.getLastError()

null

#可以看到第二条数据并没有被更新掉。因为mongo会首先匹配到第一条记录，尝试将其更新为x，但此时会与第二条记录产生主键重复，所以mongo会直接退出，且没有提示错误。

#下面我按照_id来更新第二条记录，这次就更新正常了：

> db.tianyc04.update({_id:ObjectId("510c83b113d7e50c2281b049")},x)

> db.tianyc04.find()

{ "_id" : ObjectId("510c83ad13d7e50c2281b048"), "name" : "tyc", "age" : 21 }

{ "_id" : ObjectId("510c83b113d7e50c2281b049"), "name" : "tyc", "age" : 31 }

{ "_id" : ObjectId("510c83b313d7e50c2281b04a"), "name" : "tyc", "age" : 32 }

>

下面再无聊地使用tcy条件连续更新一下，就看到mongo的更新流程了：

> db.tianyc04.update({name:'tyc'},{name:'new_line'})

> db.tianyc04.find()

{ "_id" : ObjectId("510c83ad13d7e50c2281b048"), "name" : "new_line" }

{ "_id" : ObjectId("510c83b113d7e50c2281b049"), "name" : "tyc", "age" : 31 }

{ "_id" : ObjectId("510c83b313d7e50c2281b04a"), "name" : "tyc", "age" : 32 }

> db.tianyc04.update({name:'tyc'},{xjbu:'bengcaca'})

> db.tianyc04.find()

{ "_id" : ObjectId("510c83ad13d7e50c2281b048"), "name" : "new_line" }

{ "_id" : ObjectId("510c83b113d7e50c2281b049"), "xjbu" : "bengcaca" }

{ "_id" : ObjectId("510c83b313d7e50c2281b04a"), "name" : "tyc", "age" : 32 }

> db.tianyc04.update({name:'tyc'},{tonight:'papapa'})

> db.tianyc04.find()

{ "_id" : ObjectId("510c83ad13d7e50c2281b048"), "name" : "new_line" }

{ "_id" : ObjectId("510c83b113d7e50c2281b049"), "xjbu" : "bengcaca" }

{ "_id" : ObjectId("510c83b313d7e50c2281b04a"), "tonight" : "papapa" }

>

总结：更新时的查询条件建议选择_id。

除了查询条件，还可以使用修改器对文档进行更新。

1. $inc

> db.tianyc03.find()

{ "_id" : ObjectId("50ea6b6f12729d90ce6e341b"), "name" : "xtt", "age" : 11 }

> db.tianyc03.update({name:'xtt',age:11},{'$inc':{age:5}})

> db.tianyc03.find()

{ "_id" : ObjectId("50ea6b6f12729d90ce6e341b"), "name" : "xtt", "age" : 16 }

#$inc还可以添加列。

> db.tianyc04.find()

{ "_id" : ObjectId("510c83ad13d7e50c2281b048"), "wc" : 1 }

> db.tianyc04.update({wc:1},{$inc:{score:50}})

> db.tianyc04.find()

{ "_id" : ObjectId("510c83ad13d7e50c2281b048"), "score" : 50, "wc" : 1 }

>

2. $set

用来指定一个键的值，若该键不存在，则创建。如果需要删除该键，使用$unset。

#新增加列sex

> db.tianyc03.update({name:'xtt',age:16},{$set:{sex:'m'}})

> db.tianyc03.find()

{ "_id" : ObjectId("50ea6b6f12729d90ce6e341b"), "age" : 16, "name" : "xtt", "sex" : "m" }

#修改列sex

> db.tianyc03.update({name:'xtt',age:16},{$set:{sex:'male'}})

> db.tianyc03.find()

{ "_id" : ObjectId("50ea6b6f12729d90ce6e341b"), "age" : 16, "name" : "xtt", "sex" : "male" }

#改变列sex数据类型

> db.tianyc03.update({name:'xtt',age:16},{$set:{sex:1}})

> db.tianyc03.find()

{ "_id" : ObjectId("50ea6b6f12729d90ce6e341b"), "age" : 16, "name" : "xtt", "sex" : 1 }

#删除列sex

> db.tianyc03.update({name:'xtt',age:16},{$unset:{sex:1}})

> db.tianyc03.find()

{ "_id" : ObjectId("50ea6b6f12729d90ce6e341b"), "age" : 16, "name" : "xtt" }

3. $push

用来增加数组。若没有改列，则会自动增加。

> db.tianyc03.find()

{ "_id" : ObjectId("50ea6b6f12729d90ce6e341b"), "age" : 16, "name" : "xtt" }

> db.tianyc03.update({'name':'xtt'},{$push:{companies:'neu'}})

> db.tianyc03.find()

{ "_id" : ObjectId("50ea6b6f12729d90ce6e341b"), "age" : 16, "companies" : [ "neu" ], "name" : "xtt" }

> db.tianyc03.update({'name':'xtt'},{$push:{companies:'alibaba'}})

> db.tianyc03.find()

{ "_id" : ObjectId("50ea6b6f12729d90ce6e341b"), "age" : 16, "companies" : [ "neu", "alibaba" ], "name" : "xtt" }

4. $addToSet

#push操作不会检查数组中元素是否重复，如果需要将不重复的数据加入数组，需要使用$addToSet

> db.tianyc03.update({'name':'xtt'},{$addToSet:{companies:'alibaba'}})

> db.tianyc03.find()

{ "_id" : ObjectId("50ea6b6f12729d90ce6e341b"), "age" : 16, "companies" : [ "neu", "alibaba", "alibaba" ], "name" : "xtt" }

> db.tianyc03.update({'name':'xtt'},{$addToSet:{companies:'congxing'}})

> db.tianyc03.find()

{ "_id" : ObjectId("50ea6b6f12729d90ce6e341b"), "age" : 16, "companies" : [ "neu", "alibaba", "alibaba", "congxing" ], "name" : "xtt" }

> db.tianyc03.update({'name':'xtt'},{$addToSet:{companies:'congxing'}})

> db.tianyc03.find()

{ "_id" : ObjectId("50ea6b6f12729d90ce6e341b"), "age" : 16, "companies" : [ "neu", "alibaba", "alibaba", "congxing" ], "name" : "xtt" }

>

5. $pop

通过$pop可以从数组中移除数据。此时数据被看成是一个队列。使用{$pop:{key:1}}将从队列末尾移除元素，使用{$pop:{key:-1}}将从队列开头移除元素。

> db.tianyc03.update({'name':'xtt'},{$addToSet:{companies:['c1','c2']}})

> db.tianyc03.find()

{ "_id" : ObjectId("50ea6b6f12729d90ce6e341b"), "age" : 16, "companies" : [ "neu", "alibaba", "alibaba", "congxing", [ "c1", "c2" ] ], "name" : "xtt" }

> db.tianyc03.update({'name':'xtt'},{$pop:{companies:1}})

> db.tianyc03.find()

{ "_id" : ObjectId("50ea6b6f12729d90ce6e341b"), "age" : 16, "companies" : [ "neu", "alibaba", "alibaba", "congxing" ], "name" : "xtt" }

>

> db.tianyc03.update({'name':'xtt'},{$pop:{companies:-1}})

> db.tianyc03.find()

{ "_id" : ObjectId("50ea6b6f12729d90ce6e341b"), "age" : 16, "companies" : [ "alibaba", "alibaba", "congxing" ], "name" : "xtt" }

>

6. $pull

除了 $pop，也可以使用 $pull 来删除数组中的元素，此时可以根据元素值进行匹配，将匹配上的元素全部删除。

> db.tianyc03.update({'name':'xtt'},{$addToSet:{companies:'teletek'}})

> db.tianyc03.find()

{ "_id" : ObjectId("50ea6b6f12729d90ce6e341b"), "age" : 16, "companies" : [ "alibaba", "alibaba", "congxing", "teletek" ], "name" : "xtt" }

> db.tianyc03.update({},{$pull:{companies:'congxing'}})

> db.tianyc03.find()

{ "_id" : ObjectId("50ea6b6f12729d90ce6e341b"), "age" : 16, "companies" : [ "alibaba", "alibaba", "teletek" ], "name" : "xtt" }

> db.tianyc03.update({},{$pull:{companies:'alibaba'}})

> db.tianyc03.find()

{ "_id" : ObjectId("50ea6b6f12729d90ce6e341b"), "age" : 16, "companies" : [ "teletek" ], "name" : "xtt" }

>

1. upsert

将update的第三个参数设置为true，存在则更新，不存在则插入。

> db.tianyc03.find()

{ "_id" : ObjectId("50ea6b6f12729d90ce6e341b"), "age" : 16, "companies" : [ "teletek" ], "name" : "xtt" }

> db.tianyc03.update({count:20},{$inc:{count:3}}, true)

> db.tianyc03.find()

{ "_id" : ObjectId("50ea6b6f12729d90ce6e341b"), "age" : 16, "companies" : [ "teletek" ], "name" : "xtt" }

{ "_id" : ObjectId("510f1a9f6010b3da16ea6618"), "count" : 23 }

> db.tianyc03.update({count:20},{$inc:{count:3}}, true)

> db.tianyc03.find()

{ "_id" : ObjectId("50ea6b6f12729d90ce6e341b"), "age" : 16, "companies" : [ "teletek" ], "name" : "xtt" }

{ "_id" : ObjectId("510f1a9f6010b3da16ea6618"), "count" : 23 }

{ "_id" : ObjectId("510f1aa76010b3da16ea6619"), "count" : 23 }

> db.tianyc03.update({count:23},{$inc:{count:3}}, true)

> db.tianyc03.find()

{ "_id" : ObjectId("50ea6b6f12729d90ce6e341b"), "age" : 16, "companies" : [ "teletek" ], "name" : "xtt" }

{ "_id" : ObjectId("510f1a9f6010b3da16ea6618"), "count" : 26 }

{ "_id" : ObjectId("510f1aa76010b3da16ea6619"), "count" : 23 }

>

2. save

若文档中不包含_id，save和insert功能相同；若包含_id，则save和upsert功能相同。

> db.tianyc03.find()

{ "_id" : ObjectId("50ea6b6f12729d90ce6e341b"), "age" : 16, "companies" : [ "teletek" ], "name" : "xtt" }

{ "_id" : ObjectId("510f1a9f6010b3da16ea6618"), "count" : 26 }

{ "_id" : ObjectId("510f1aa76010b3da16ea6619"), "count" : 23 }

> db.tianyc03.save({count:24})

> db.tianyc03.find()

{ "_id" : ObjectId("50ea6b6f12729d90ce6e341b"), "age" : 16, "companies" : [ "teletek" ], "name" : "xtt" }

{ "_id" : ObjectId("510f1a9f6010b3da16ea6618"), "count" : 26 }

{ "_id" : ObjectId("510f1aa76010b3da16ea6619"), "count" : 23 }

{ "_id" : ObjectId("510f1b718474cd8af024e2d0"), "count" : 24 }

> db.tianyc03.save({count:24})

> db.tianyc03.find()

{ "_id" : ObjectId("50ea6b6f12729d90ce6e341b"), "age" : 16, "companies" : [ "teletek" ], "name" : "xtt" }

{ "_id" : ObjectId("510f1a9f6010b3da16ea6618"), "count" : 26 }

{ "_id" : ObjectId("510f1aa76010b3da16ea6619"), "count" : 23 }

{ "_id" : ObjectId("510f1b718474cd8af024e2d0"), "count" : 24 }

{ "_id" : ObjectId("510f1c8f8474cd8af024e2d1"),"count" : 24 }

> db.tianyc03.save({"_id" : ObjectId("510f1b718474cd8af024e2d0"),count:244})

> db.tianyc03.find()

{ "_id" : ObjectId("50ea6b6f12729d90ce6e341b"), "age" : 16, "companies" : [ "teletek" ], "name" : "xtt" }

{ "_id" : ObjectId("510f1a9f6010b3da16ea6618"), "count" : 26 }

{ "_id" : ObjectId("510f1aa76010b3da16ea6619"), "count" : 23 }

{ "_id" : ObjectId("510f1b718474cd8af024e2d0"), "count" : 244 }

{ "_id" : ObjectId("510f1c8f8474cd8af024e2d1"),"count" : 24 }

#而insert会提示插入失败。

> db.tianyc03.insert({"_id" : ObjectId("510f1b718474cd8af024e2d0"),count:244})

E11000 duplicate key error index: test.tianyc03.$_id_ dup key: { : ObjectId('510f1b718474cd8af024e2d0') }

3. 批量更新

默认情况下，update只更新匹配到的第一行记录。将update的第四个参数设置为true，则批量更新搜索到的所有记录。

> db.tianyc03.find()

{ "_id" : ObjectId("50ea6b6f12729d90ce6e341b"), "count" : 11 }

{ "_id" : ObjectId("510f1a9f6010b3da16ea6618"), "count" : 26 }

{ "_id" : ObjectId("510f1aa76010b3da16ea6619"), "count" : 23 }

{ "_id" : ObjectId("510f1b718474cd8af024e2d0"), "count" : 244 }

{ "_id" : ObjectId("510f1c8f8474cd8af024e2d1"), "count" : 24 }

#将所有count值增加10，但却只增加了第一行。

> db.tianyc03.update({},{$inc:{count:10}})

> db.tianyc03.find()

{ "_id" : ObjectId("50ea6b6f12729d90ce6e341b"), "count" : 21 }

{ "_id" : ObjectId("510f1a9f6010b3da16ea6618"), "count" : 26 }

{ "_id" : ObjectId("510f1aa76010b3da16ea6619"), "count" : 23 }

{ "_id" : ObjectId("510f1b718474cd8af024e2d0"), "count" : 244 }

{ "_id" : ObjectId("510f1c8f8474cd8af024e2d1"), "count" : 24 }

#再增加一次，还是只增加了第一行。

> db.tianyc03.update({},{$inc:{count:10}})

> db.tianyc03.find()

{ "_id" : ObjectId("50ea6b6f12729d90ce6e341b"), "count" : 31 }

{ "_id" : ObjectId("510f1a9f6010b3da16ea6618"), "count" : 26 }

{ "_id" : ObjectId("510f1aa76010b3da16ea6619"), "count" : 23 }

{ "_id" : ObjectId("510f1b718474cd8af024e2d0"), "count" : 244 }

{ "_id" : ObjectId("510f1c8f8474cd8af024e2d1"), "count" : 24 }

#使用批量更新，达到目的。

> db.tianyc03.update({},{$inc:{count:10}},false,true)

> db.tianyc03.find()

{ "_id" : ObjectId("50ea6b6f12729d90ce6e341b"), "count" : 41 }

{ "_id" : ObjectId("510f1a9f6010b3da16ea6618"), "count" : 36 }

{ "_id" : ObjectId("510f1aa76010b3da16ea6619"), "count" : 33 }

{ "_id" : ObjectId("510f1b718474cd8af024e2d0"), "count" : 254 }

{ "_id" : ObjectId("510f1c8f8474cd8af024e2d1"), "count" : 34 }