MongoDB命令行操作(下)

接上篇，这里主要介绍利用Mongodb的cli对集合中的记录进行增删改查的操作，简单地说，就是Record级别上进行的操作。

从这里开始，我们用事先存在的(上)中提到的blogtest数据库做测试，其中有两个Collection，一个是book，另一个是user。

1 插入操作

1.1 向user集合中插入两条记录
> db.user.insert({'name':'Gal Gadot','gender':'female','age':28,'salary':11000})
> db.user.insert({'name':'Mikie Hara','gender':'female','age':26,'salary':7000})

1.2 同样也可以用save完成类似的插入操作
> db.user.save({'name':'Wentworth Earl Miller','gender':'male','age':41,'salary':33000})

2 查找操作

2.1 查找集合中的所有记录

> db.user.find()
{ "_id" : ObjectId("52442736d8947fb501000001"), "name" : "lfqy", "gender" : "male", "age" : 23, "salary" : 15 }
{ "_id" : ObjectId("52453cfb25e437dfea8fd4f4"), "name" : "Gal Gadot", "gender" : "female", "age" : 28, "salary" : 11000 }
{ "_id" : ObjectId("52453d8525e437dfea8fd4f5"), "name" : "Mikie Hara", "gender" : "female", "age" : 26, "salary" : 7000 }
{ "_id" : ObjectId("52453e2125e437dfea8fd4f6"), "name" : "Wentworth Earl Miller", "gender" : "male", "age" : 41, "salary" : 33000 }
{ "_id" : ObjectId("52454155d8947fb70d000000"), "name" : "not known", "sex_orientation" : "male", "age" : 13 }

2.2 查找集合中的符合条件的记录

(1)单一条件
a)Exact Equal:
查询age为了23的数据
> db.user.find({"age":23})
{ "_id" : ObjectId("52442736d8947fb501000001"), "name" : "lfqy", "gender" : "male", "age" : 23, "salary" : 15 }
b)Great Than:
查询salary大于5000的数据
> db.user.find({salary:{$gt:5000}})
{ "_id" : ObjectId("52453cfb25e437dfea8fd4f4"), "name" : "Gal Gadot", "gender" : "female", "age" : 28, "salary" : 11000 }
{ "_id" : ObjectId("52453d8525e437dfea8fd4f5"), "name" : "Mikie Hara", "gender" : "female", "age" : 26, "salary" : 7000 }
{ "_id" : ObjectId("52453e2125e437dfea8fd4f6"), "name" : "Wentworth Earl Miller", "gender" : "male", "age" : 41, "salary" : 33000 }
c)Fuzzy Match
查询name中包含'a'的数据
> db.user.find({name:/a/})
{ "_id" : ObjectId("52453cfb25e437dfea8fd4f4"), "name" : "Gal Gadot", "gender" : "female", "age" : 28, "salary" : 11000 }
{ "_id" : ObjectId("52453d8525e437dfea8fd4f5"), "name" : "Mikie Hara", "gender" : "female", "age" : 26, "salary" : 7000 }
{ "_id" : ObjectId("52453e2125e437dfea8fd4f6"), "name" : "Wentworth Earl Miller", "gender" : "male", "age" : 41, "salary" : 33000 }
查询name以G打头的数据
> db.user.find({name:/^G/})
{ "_id" : ObjectId("52453cfb25e437dfea8fd4f4"), "name" : "Gal Gadot", "gender" : "female", "age" : 28, "salary" : 11000 }

(2)多条件"与"
查询age小于30，salary大于6000的数据
> db.user.find({age:{$lt:30},salary:{$gt:6000}})
{ "_id" : ObjectId("52453cfb25e437dfea8fd4f4"), "name" : "Gal Gadot", "gender" : "female", "age" : 28, "salary" : 11000 }
{ "_id" : ObjectId("52453d8525e437dfea8fd4f5"), "name" : "Mikie Hara", "gender" : "female", "age" : 26, "salary" : 7000 }
{ "_id" : ObjectId("52454155d8947fb70d000000"), "name" : "not known", "sex_orientation" : "male", "age" : 13, "salary" : 30000 }

(3)多条件"或"
查询age小于25，或者salary大于10000的记录
> db.user.find({$or:[{salary:{$gt:10000}},{age:{$lt:25}}]})
{ "_id" : ObjectId("52442736d8947fb501000001"), "name" : "lfqy", "gender" : "male", "age" : 23, "salary" : 15 }
{ "_id" : ObjectId("52453cfb25e437dfea8fd4f4"), "name" : "Gal Gadot", "gender" : "female", "age" : 28, "salary" : 11000 }
{ "_id" : ObjectId("52453e2125e437dfea8fd4f6"), "name" : "Wentworth Earl Miller", "gender" : "male", "age" : 41, "salary" : 33000 }
{ "_id" : ObjectId("52454155d8947fb70d000000"), "name" : "not known", "sex_orientation" : "male", "age" : 13, "salary" : 30000 }

(4)不等于查询
查询年龄不等于23的记录(这里返回结果中，会包含没有年龄字段的记录)
> db.user.find({"age":{ $ne: 23}})
{ "_id" : ObjectId("52453cfb25e437dfea8fd4f4"), "name" : "Gal Gadot", "gender" : "female", "age" : 28, "salary" : 11050 }
{ "_id" : ObjectId("52453d8525e437dfea8fd4f5"), "name" : "Mikie Hara", "gender" : "female", "age" : 26, "salary" : 7050 }
{ "_id" : ObjectId("52453e2125e437dfea8fd4f6"), "name" : "Wentworth Earl Miller", "gender" : "male", "age" : 41, "salary" : 33000 }
{ "_id" : ObjectId("52454155d8947fb70d000000"), "name" : "not known", "sex_orientation" : "male", "age" : 13, "salary" : 30000 }
{ "_id" : ObjectId("524562d681c83a5bf26fc286"), "gender" : "female1", "salary" : 50 }
{ "_id" : ObjectId("524563e881c83a5bf26fc287"), "gender" : "x" }
{ "_id" : ObjectId("5245648081c83a5bf26fc288"), "gender" : "x" }
{ "_id" : ObjectId("5245648e81c83a5bf26fc289"), "age" : "x" }
{ "_id" : ObjectId("524564c181c83a5bf26fc28a"), "age" : "x", "gender" : 4 }

(5)利用正则表达式的查询
查询名字中含有字母E的记录(i表示忽略大小写)
> db.user.find({name:/E/i})
也可以用：
> db.user.find({name:{$regex:'E',$options:'i'}})
{ "_id" : ObjectId("52453d8525e437dfea8fd4f5"), "age" : 26, "ex" : "barrymore", "gender" : "female", "name" : "Mikie Hara", "salary" : 7050 }
{ "_id" : ObjectId("52453e2125e437dfea8fd4f6"), "age" : 41, "ex" : "barrymore", "gender" : "male", "name" : "Wentworth Earl Miller", "salary" : 33000 }
查询名字中含有字母E的记录(默认区分大小写)
> db.user.find({name:/E/})
等价于：
> db.user.find({name:{$regex:'E'}})
{ "_id" : ObjectId("52453e2125e437dfea8fd4f6"), "age" : 41, "ex" : "barrymore", "gender" : "male", "name" : "Wentworth Earl Miller", "salary" : 33000 }
查询某个字段以“.0”结尾的记录
db.user.find(name:/\.0$/)
这里的"//"中的内容表示是正则表达式，"."需要转义，"$"符号表示结尾。

2.3 查询第一条记录
将上面的find替换为findOne()可以查找符合条件的第一条记录。

将上面的find替换为findOne()可以查找符合条件的第一条记录。
> db.user.findOne({$or:[{salary:{$gt:10000}},{age:{$lt:25}}]})
{
	"_id" : ObjectId("52442736d8947fb501000001"),
	"name" : "lfqy",
	"gender" : "male",
	"age" : 23,
	"salary" : 15
}

2.4 查询记录的指定字段

查询user集合中所有记录的name,age,salary,sex_orientation字段
> db.user.find({},{name:1,age:1,salary:1,sex_orientation:true})
{ "_id" : ObjectId("52442736d8947fb501000001"), "name" : "lfqy", "age" : 23, "salary" : 15 }
{ "_id" : ObjectId("52453cfb25e437dfea8fd4f4"), "name" : "Gal Gadot", "age" : 28, "salary" : 11000 }
{ "_id" : ObjectId("52453d8525e437dfea8fd4f5"), "name" : "Mikie Hara", "age" : 26, "salary" : 7000 }
{ "_id" : ObjectId("52453e2125e437dfea8fd4f6"), "name" : "Wentworth Earl Miller", "age" : 41, "salary" : 33000 }
{ "_id" : ObjectId("52454155d8947fb70d000000"), "name" : "not known", "sex_orientation" : "male", "age" : 13, "salary" : 30000 }
注意：这里的1表示显示此列的意思，也可以用true表示。
可以看到，默认_id，字段都是显示的。如果要其不显示，只需将其显示指定为false:
> db.user.find({},{name:1,age:1,salary:1,sex_orientation:true,_id:false})

2.5 查询指定字段的数据，并去重。

查询gender字段的数据，并去掉重复数据
> db.user.distinct('gender')
[ "male", "female" ]

2.6 对查询结果集的操作

(1)Pretty Print
为了方便，mongo也提供了pretty print工具，db.collection.pretty()或者是db.collection.forEach(printjson)
> db.user.find().pretty()
{
	"_id" : ObjectId("52442736d8947fb501000001"),
	"name" : "lfqy",
	"gender" : "male",
	"age" : 23,
	"salary" : 15
}
{
	"_id" : ObjectId("52453cfb25e437dfea8fd4f4"),
	"name" : "Gal Gadot",
	"gender" : "female",
	"age" : 28,
	"salary" : 11000
}
{
	"_id" : ObjectId("52453d8525e437dfea8fd4f5"),
	"name" : "Mikie Hara",
	"gender" : "female",
	"age" : 26,
	"salary" : 7000
}
{
	"_id" : ObjectId("52453e2125e437dfea8fd4f6"),
	"name" : "Wentworth Earl Miller",
	"gender" : "male",
	"age" : 41,
	"salary" : 33000
}
{
	"_id" : ObjectId("52454155d8947fb70d000000"),
	"name" : "not known",
	"sex_orientation" : "male",
	"age" : 13
}
(2)指定结果集显示的条目
a)显示结果集中的前3条记录
> db.user.find().limit(3)
{ "_id" : ObjectId("52442736d8947fb501000001"), "name" : "lfqy", "gender" : "male", "age" : 23, "salary" : 15 }
{ "_id" : ObjectId("52453cfb25e437dfea8fd4f4"), "name" : "Gal Gadot", "gender" : "female", "age" : 28, "salary" : 11000 }
{ "_id" : ObjectId("52453d8525e437dfea8fd4f5"), "name" : "Mikie Hara", "gender" : "female", "age" : 26, "salary" : 7000 }
b)查询第1条以后的所有数据
> db.user.find().skip(1)
{ "_id" : ObjectId("52453cfb25e437dfea8fd4f4"), "name" : "Gal Gadot", "gender" : "female", "age" : 28, "salary" : 11000 }
{ "_id" : ObjectId("52453d8525e437dfea8fd4f5"), "name" : "Mikie Hara", "gender" : "female", "age" : 26, "salary" : 7000 }
{ "_id" : ObjectId("52453e2125e437dfea8fd4f6"), "name" : "Wentworth Earl Miller", "gender" : "male", "age" : 41, "salary" : 33000 }
{ "_id" : ObjectId("52454155d8947fb70d000000"), "name" : "not known", "sex_orientation" : "male", "age" : 13, "salary" : 30000 }
c)对结果集排序
升序
> db.user.find().sort({salary:1})
{ "_id" : ObjectId("52442736d8947fb501000001"), "name" : "lfqy", "gender" : "male", "age" : 23, "salary" : 15 }
{ "_id" : ObjectId("52453d8525e437dfea8fd4f5"), "name" : "Mikie Hara", "gender" : "female", "age" : 26, "salary" : 7000 }
{ "_id" : ObjectId("52453cfb25e437dfea8fd4f4"), "name" : "Gal Gadot", "gender" : "female", "age" : 28, "salary" : 11000 }
{ "_id" : ObjectId("52454155d8947fb70d000000"), "name" : "not known", "sex_orientation" : "male", "age" : 13, "salary" : 30000 }
{ "_id" : ObjectId("52453e2125e437dfea8fd4f6"), "name" : "Wentworth Earl Miller", "gender" : "male", "age" : 41, "salary" : 33000 }
降序
> db.user.find().sort({salary:-1})
{ "_id" : ObjectId("52453e2125e437dfea8fd4f6"), "name" : "Wentworth Earl Miller", "gender" : "male", "age" : 41, "salary" : 33000 }
{ "_id" : ObjectId("52454155d8947fb70d000000"), "name" : "not known", "sex_orientation" : "male", "age" : 13, "salary" : 30000 }
{ "_id" : ObjectId("52453cfb25e437dfea8fd4f4"), "name" : "Gal Gadot", "gender" : "female", "age" : 28, "salary" : 11000 }
{ "_id" : ObjectId("52453d8525e437dfea8fd4f5"), "name" : "Mikie Hara", "gender" : "female", "age" : 26, "salary" : 7000 }
{ "_id" : ObjectId("52442736d8947fb501000001"), "name" : "lfqy", "gender" : "male", "age" : 23, "salary" : 15 }

也可以将排序依据的字段，写在一个list里面，如下：
> db.user.find().sort([("salary",1),("name",-1)])

2.7 统计查询结果中记录的条数

(1)统计集合中的所有记录条数
> db.user.find().count()
5
(2)查询符合条件的记录数
查询salary小于4000或大于10000的记录数
> db.user.find({$or: [{salary: {$lt:4000}}, {salary: {$gt:10000}}]}).count()
4

2.8 查询存在(或不存在)指定字段的记录

查询不存在age字段，但是有gender字段，并且ex为barrymore的记录。

> db.user.find({"age":{$exists:false},"gender":{$exists:true},"ex":"barrymore"})
{ "_id" : ObjectId("524562d681c83a5bf26fc286"), "ex" : "barrymore", "gender" : "female1", "salary" : 50 }
{ "_id" : ObjectId("524563e881c83a5bf26fc287"), "ex" : "barrymore", "gender" : "x" }
{ "_id" : ObjectId("5245648081c83a5bf26fc288"), "ex" : "barrymore", "gender" : "x" }

3 删除操作

3.1 删除整个集合中的所有数据

> db.test.insert({name:"asdf"})
> show collections
book
system.indexes
test
user
到这里新建了一个集合，名为test。
删除test中的所有记录。
> db.test.remove()
PRIMARY> show collections
book
system.indexes
test
user
> db.test.find()
可见test中的记录全部被删除。
注意db.collection.remove()和drop()的区别，remove()只是删除了集合中所有的记录，而集合中原有的索引等信息还在，而drop()则把集合相关信息整个删除(包括索引)。

3.2 删除集合中符合条件的所有记录

> db.user.remove({name:'lfqy'})
> db.user.find()
{ "_id" : ObjectId("52453cfb25e437dfea8fd4f4"), "name" : "Gal Gadot", "gender" : "female", "age" : 28, "salary" : 11000 }
{ "_id" : ObjectId("52453d8525e437dfea8fd4f5"), "name" : "Mikie Hara", "gender" : "female", "age" : 26, "salary" : 7000 }
{ "_id" : ObjectId("52453e2125e437dfea8fd4f6"), "name" : "Wentworth Earl Miller", "gender" : "male", "age" : 41, "salary" : 33000 }
{ "_id" : ObjectId("52454155d8947fb70d000000"), "name" : "not known", "sex_orientation" : "male", "age" : 13, "salary" : 30000 }

> db.user.find()
{ "_id" : ObjectId("52453cfb25e437dfea8fd4f4"), "name" : "Gal Gadot", "gender" : "female", "age" : 28, "salary" : 11000 }
{ "_id" : ObjectId("52453d8525e437dfea8fd4f5"), "name" : "Mikie Hara", "gender" : "female", "age" : 26, "salary" : 7000 }
{ "_id" : ObjectId("52453e2125e437dfea8fd4f6"), "name" : "Wentworth Earl Miller", "gender" : "male", "age" : 41, "salary" : 33000 }
{ "_id" : ObjectId("52454155d8947fb70d000000"), "name" : "not known", "sex_orientation" : "male", "age" : 13, "salary" : 30000 }
{ "_id" : ObjectId("52455cc825e437dfea8fd4f8"), "name" : "2", "gender" : "female", "age" : 28, "salary" : 2 }
{ "_id" : ObjectId("52455d8a25e437dfea8fd4fa"), "name" : "1", "gender" : "female", "age" : 28, "salary" : 1 }
> db.user.remove( {salary :{$lt:10}})
> db.user.find()
{ "_id" : ObjectId("52453cfb25e437dfea8fd4f4"), "name" : "Gal Gadot", "gender" : "female", "age" : 28, "salary" : 11000 }
{ "_id" : ObjectId("52453d8525e437dfea8fd4f5"), "name" : "Mikie Hara", "gender" : "female", "age" : 26, "salary" : 7000 }
{ "_id" : ObjectId("52453e2125e437dfea8fd4f6"), "name" : "Wentworth Earl Miller", "gender" : "male", "age" : 41, "salary" : 33000 }
{ "_id" : ObjectId("52454155d8947fb70d000000"), "name" : "not known", "sex_orientation" : "male", "age" : 13, "salary" : 30000 }

3.3  删除集合中符合条件的一条记录

> db.user.find()
{ "_id" : ObjectId("52453cfb25e437dfea8fd4f4"), "name" : "Gal Gadot", "gender" : "female", "age" : 28, "salary" : 11000 }
{ "_id" : ObjectId("52453d8525e437dfea8fd4f5"), "name" : "Mikie Hara", "gender" : "female", "age" : 26, "salary" : 7000 }
{ "_id" : ObjectId("52453e2125e437dfea8fd4f6"), "name" : "Wentworth Earl Miller", "gender" : "male", "age" : 41, "salary" : 33000 }
{ "_id" : ObjectId("52454155d8947fb70d000000"), "name" : "not known", "sex_orientation" : "male", "age" : 13, "salary" : 30000 }
{ "_id" : ObjectId("52455de325e437dfea8fd4fb"), "name" : "1", "gender" : "female", "age" : 28, "salary" : 1 }
{ "_id" : ObjectId("52455de925e437dfea8fd4fc"), "name" : "2", "gender" : "female", "age" : 28, "salary" : 2 }
> db.user.remove({salary :{$lt:10}},1)
> db.user.find()
{ "_id" : ObjectId("52453cfb25e437dfea8fd4f4"), "name" : "Gal Gadot", "gender" : "female", "age" : 28, "salary" : 11000 }
{ "_id" : ObjectId("52453d8525e437dfea8fd4f5"), "name" : "Mikie Hara", "gender" : "female", "age" : 26, "salary" : 7000 }
{ "_id" : ObjectId("52453e2125e437dfea8fd4f6"), "name" : "Wentworth Earl Miller", "gender" : "male", "age" : 41, "salary" : 33000 }
{ "_id" : ObjectId("52454155d8947fb70d000000"), "name" : "not known", "sex_orientation" : "male", "age" : 13, "salary" : 30000 }
{ "_id" : ObjectId("52455de925e437dfea8fd4fc"), "name" : "2", "gender" : "female", "age" : 28, "salary" : 2 }
当然，也可以是db.user.remove({salary :{$lt:10}},true)

4 更新操作

4.1 赋值更新
db.collection.update(criteria, objNew, upsert, multi )
criteria:update的查询条件，类似sql update查询内where后面的
objNew:update的对象和一些更新的操作符（如$,$inc...）等，也可以理解为sql update查询内set后面的。
upsert : 如果不存在update的记录，是否插入objNew,true为插入，默认是false，不插入。
multi : mongodb默认是false,只更新找到的第一条记录，如果这个参数为true,就把按条件查出来多条记录全部更新。

> db.user.find()
{ "_id" : ObjectId("52453cfb25e437dfea8fd4f4"), "name" : "Gal Gadot", "gender" : "female", "age" : 28, "salary" : 11000 }
{ "_id" : ObjectId("52453d8525e437dfea8fd4f5"), "name" : "Mikie Hara", "gender" : "female", "age" : 26, "salary" : 7000 }
{ "_id" : ObjectId("52453e2125e437dfea8fd4f6"), "name" : "Wentworth Earl Miller", "gender" : "male", "age" : 41, "salary" : 33000 }
{ "_id" : ObjectId("52454155d8947fb70d000000"), "name" : "not known", "sex_orientation" : "male", "age" : 13, "salary" : 30000 }
{ "_id" : ObjectId("52455f8925e437dfea8fd4fd"), "name" : "lfqy", "gender" : "male", "age" : 28, "salary" : 1 }
{ "_id" : ObjectId("5245607525e437dfea8fd4fe"), "name" : "lfqy", "gender" : "male", "age" : 28, "salary" : 2 }
> db.user.update({name:'lfqy'},{$set:{age:23}},false,true)
> db.user.find()
{ "_id" : ObjectId("52453cfb25e437dfea8fd4f4"), "name" : "Gal Gadot", "gender" : "female", "age" : 28, "salary" : 11000 }
{ "_id" : ObjectId("52453d8525e437dfea8fd4f5"), "name" : "Mikie Hara", "gender" : "female", "age" : 26, "salary" : 7000 }
{ "_id" : ObjectId("52453e2125e437dfea8fd4f6"), "name" : "Wentworth Earl Miller", "gender" : "male", "age" : 41, "salary" : 33000 }
{ "_id" : ObjectId("52454155d8947fb70d000000"), "name" : "not known", "sex_orientation" : "male", "age" : 13, "salary" : 30000 }
{ "_id" : ObjectId("52455f8925e437dfea8fd4fd"), "name" : "lfqy", "gender" : "male", "age" : 23, "salary" : 1 }
{ "_id" : ObjectId("5245607525e437dfea8fd4fe"), "name" : "lfqy", "gender" : "male", "age" : 23, "salary" : 2 }
db.user.find()
{ "_id" : ObjectId("52453cfb25e437dfea8fd4f4"), "name" : "Gal Gadot", "gender" : "female", "age" : 28, "salary" : 11000 }
{ "_id" : ObjectId("52453d8525e437dfea8fd4f5"), "name" : "Mikie Hara", "gender" : "female", "age" : 26, "salary" : 7000 }
{ "_id" : ObjectId("52453e2125e437dfea8fd4f6"), "name" : "Wentworth Earl Miller", "gender" : "male", "age" : 41, "salary" : 33000 }
{ "_id" : ObjectId("52454155d8947fb70d000000"), "name" : "not known", "sex_orientation" : "male", "age" : 13, "salary" : 30000 }
{ "_id" : ObjectId("52455f8925e437dfea8fd4fd"), "name" : "lfqy", "gender" : "male", "age" : 23, "salary" : 1 }
{ "_id" : ObjectId("5245607525e437dfea8fd4fe"), "name" : "lfqy", "gender" : "male", "age" : 23, "salary" : 2 }
> db.user.update({name:'lfqy1'},{$set:{age:23}},true,true)
> db.user.find()
{ "_id" : ObjectId("52453cfb25e437dfea8fd4f4"), "name" : "Gal Gadot", "gender" : "female", "age" : 28, "salary" : 11000 }
{ "_id" : ObjectId("52453d8525e437dfea8fd4f5"), "name" : "Mikie Hara", "gender" : "female", "age" : 26, "salary" : 7000 }
{ "_id" : ObjectId("52453e2125e437dfea8fd4f6"), "name" : "Wentworth Earl Miller", "gender" : "male", "age" : 41, "salary" : 33000 }
{ "_id" : ObjectId("52454155d8947fb70d000000"), "name" : "not known", "sex_orientation" : "male", "age" : 13, "salary" : 30000 }
{ "_id" : ObjectId("52455f8925e437dfea8fd4fd"), "name" : "lfqy", "gender" : "male", "age" : 23, "salary" : 1 }
{ "_id" : ObjectId("5245607525e437dfea8fd4fe"), "name" : "lfqy", "gender" : "male", "age" : 23, "salary" : 2 }
{ "_id" : ObjectId("5245610881c83a5bf26fc285"), "age" : 23, "name" : "lfqy1" }
> db.user.update({name:'lfqy'},{$set:{interest:"NBA"}},false,true)
> db.user.find()
{ "_id" : ObjectId("52453cfb25e437dfea8fd4f4"), "name" : "Gal Gadot", "gender" : "female", "age" : 28, "salary" : 11000 }
{ "_id" : ObjectId("52453d8525e437dfea8fd4f5"), "name" : "Mikie Hara", "gender" : "female", "age" : 26, "salary" : 7000 }
{ "_id" : ObjectId("52453e2125e437dfea8fd4f6"), "name" : "Wentworth Earl Miller", "gender" : "male", "age" : 41, "salary" : 33000 }
{ "_id" : ObjectId("52454155d8947fb70d000000"), "name" : "not known", "sex_orientation" : "male", "age" : 13, "salary" : 30000 }
{ "_id" : ObjectId("5245610881c83a5bf26fc285"), "age" : 23, "name" : "lfqy1" }
{ "_id" : ObjectId("52455f8925e437dfea8fd4fd"), "age" : 23, "gender" : "male", "interest" : "NBA", "name" : "lfqy", "salary" : 1 }
{ "_id" : ObjectId("5245607525e437dfea8fd4fe"), "age" : 23, "gender" : "male", "interest" : "NBA", "name" : "lfqy", "salary" : 2 }

4.2 增值更新

> db.user.find()
{ "_id" : ObjectId("52453cfb25e437dfea8fd4f4"), "name" : "Gal Gadot", "gender" : "female", "age" : 28, "salary" : 11000 }
{ "_id" : ObjectId("52453d8525e437dfea8fd4f5"), "name" : "Mikie Hara", "gender" : "female", "age" : 26, "salary" : 7000 }
{ "_id" : ObjectId("52453e2125e437dfea8fd4f6"), "name" : "Wentworth Earl Miller", "gender" : "male", "age" : 41, "salary" : 33000 }
{ "_id" : ObjectId("52454155d8947fb70d000000"), "name" : "not known", "sex_orientation" : "male", "age" : 13, "salary" : 30000 }
{ "_id" : ObjectId("5245610881c83a5bf26fc285"), "age" : 23, "name" : "lfqy1" }
{ "_id" : ObjectId("52455f8925e437dfea8fd4fd"), "age" : 23, "gender" : "male", "interest" : "NBA", "name" : "lfqy", "salary" : 1 }
{ "_id" : ObjectId("5245607525e437dfea8fd4fe"), "age" : 23, "gender" : "male", "interest" : "NBA", "name" : "lfqy", "salary" : 2 }
> db.user.update({gender:'female'},{$inc:{salary:50}},false,true)
> db.user.find()
{ "_id" : ObjectId("52453cfb25e437dfea8fd4f4"), "name" : "Gal Gadot", "gender" : "female", "age" : 28, "salary" : 11050 }
{ "_id" : ObjectId("52453d8525e437dfea8fd4f5"), "name" : "Mikie Hara", "gender" : "female", "age" : 26, "salary" : 7050 }
{ "_id" : ObjectId("52453e2125e437dfea8fd4f6"), "name" : "Wentworth Earl Miller", "gender" : "male", "age" : 41, "salary" : 33000 }
{ "_id" : ObjectId("52454155d8947fb70d000000"), "name" : "not known", "sex_orientation" : "male", "age" : 13, "salary" : 30000 }
{ "_id" : ObjectId("5245610881c83a5bf26fc285"), "age" : 23, "name" : "lfqy1" }
{ "_id" : ObjectId("52455f8925e437dfea8fd4fd"), "age" : 23, "gender" : "male", "interest" : "NBA", "name" : "lfqy", "salary" : 1 }
{ "_id" : ObjectId("5245607525e437dfea8fd4fe"), "age" : 23, "gender" : "male", "interest" : "NBA", "name" : "lfqy", "salary" : 2 }

关于更新操作（db.collection.update(criteria, objNew, upsert, multi )），要说明的是，如果upsert为true，那么在没有找到符合更新条件的情况下，mongo会在集合中插入一条记录其值满足更新条件的记录(其中的字段只有更新条件中涉及的字段，字段的值满足更新条件)，然后将其更新（注意，如果更新条件是$lt这种不等式条件，那么upsert插入的记录只会包含更新操作涉及的字段，而不会有更新条件中的字段。这也很好理解，因为没法为这种字段定值，mongo索性就不取这些字段）。如果符合条件的记录中没有要更新的字段，那么mongo会为其创建该字段，并更新。

上面大致介绍了MongoDB命令行中所涉及的操作，只是为了记录和查阅。细心的也许会发现，这篇文章，越往后我的耐心越少。期待有时间能分享一些not very navie的东西。

总之，希望对自己，对大家都有所帮助。