mongodb更新操作

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" }
>

　　转自:http://www.cnblogs.com/yuechaotian/archive/2013/02/04/2890266.html