Mongodb-基本命令

最新推荐文章于 2021-01-16 09:56:55 发布

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最新推荐文章于 2021-01-16 09:56:55 发布

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文章标签： mongodb 基本命令文档集合索引

本文链接：https://blog.youkuaiyun.com/LABLENET/article/details/47251371

1.回顾：上篇已经学习过 Mongodb的安装的两种方式

2.这篇将学习 mongodb的基本命令

3.准备：安装好mongodb后，需要先打开mongodb服务，后打开一个客户端（cmd操作）

4.创建数据库，对象和集合

4.1 新建数据库 db

use student

4.2 新建集合 Collection

db.createCollection("LABELNET");

4.3 新建文档 document

document={"name":"yuan","age":23}

4.4 查看所有数据库

show dbs

4.5 查看一个数据库下的集合状态

use student;
db.printCollectionStats();

4.6 演示结果：

> use student
switched to db student
> db.createCollection("LABELNET");
{ "ok" : 1 }
> document={"name":"yuan","age":23}
{ "name" : "yuan", "age" : 23 }
> show dbs
local    0.078GB
student  0.078GB
> use student
switched to db student
> db.printCollectionStats();
LABELNET
{
        "ns" : "student.LABELNET",
        "count" : 0,
        "size" : 0,
        "numExtents" : 1,
        "storageSize" : 8192,
        "lastExtentSize" : 8192,
        "paddingFactor" : 1,
        "paddingFactorNote" : "paddingFactor is unused and unmaintained in 3.0.
It remains hard coded to 1.0 for compatibility only.",
        "userFlags" : 1,
        "capped" : false,
        "nindexes" : 1,
        "totalIndexSize" : 8176,
        "indexSizes" : {
                "_id_" : 8176
        },
        "ok" : 1
}
---
system.indexes
{
        "ns" : "student.system.indexes",
        "count" : 1,
        "size" : 112,
        "avgObjSize" : 112,
        "numExtents" : 1,
        "storageSize" : 8192,
        "lastExtentSize" : 8192,
        "paddingFactor" : 1,
        "paddingFactorNote" : "paddingFactor is unused and unmaintained in 3.0.
It remains hard coded to 1.0 for compatibility only.",
        "userFlags" : 0,
        "capped" : false,
        "nindexes" : 0,
        "totalIndexSize" : 0,
        "indexSizes" : {

        },
        "ok" : 1
}
---
>

5. 插入操作 insert

5.1 可以先定义一个文档document ，后将文档插入到集合中。或者直接将输入插入到集合中。

5.2 基本格式

db.集合名称.insert(已定义的文档);

db.集合名称.insert(数据);

5.3 演示示例

---
> db.LABELNET.insert({"name":"csdn","age":"老大了！"});
WriteResult({ "nInserted" : 1 })
> document={"name":"yuan",age:"23"};
{ "name" : "yuan", "age" : "23" }
> db.LABELNET.insert(document);
WriteResult({ "nInserted" : 1 })

6. 查询操作 find

6.1 基本格式

（1）db.集合名称.find();显示文档

（2）db.集合名称.find(where);

（3）db.集合名称.find({"name":{$type:2}});

6.2 基本查询

> db.LABELNET.find();
{ "_id" : ObjectId("55bec40532cbb5faa25c967c"), "name" : "csdn", "age" : "老大了
！" }
{ "_id" : ObjectId("55bec43732cbb5faa25c967d"), "name" : "yuan", "age" : "23" }

6.3 条件查询

$type操作符是基于BSON类型来检索集合中匹配的结果。

db.集合名称.find({"name":{$type:2}});

$type 对应得值有下面几种：

         Double 1 
	 String 2 
	 Object 3 
	 Array 4 
	 Binary data 5 
	 Object id 7 
	 Boolean 8 
         Date 9 
         Null 10 
         Regular expression 11 
         JavaScript code 13 
         Symbol 14 
         JavaScript code with scope 15 
         32-bit integer 16 
         Timestamp 17 
         64-bit integer 18 
         Min key 255 
         Max key 127

演示示例：

> db.LABELNET.find({"name":"yuan"});
{ "_id" : ObjectId("55bec43732cbb5faa25c967d"), "name" : "yuan", "age" : "23" }
> db.LABELNET.find({"name":{$type:2}});
{ "_id" : ObjectId("55bec40532cbb5faa25c967c"), "name" : "csdn", "age" : "老大了
！" }
{ "_id" : ObjectId("55bec43732cbb5faa25c967d"), "name" : "yuan", "age" : "23" }
>

6.4 满足条件的，取固定条数： db.集合名称.find({条件}).limit(10);

7.修改数据 update

7.1基本格式 : 注意条件

db.集合名称.update(where,set,未找到插入新的为true,更新多条为true);

7.2 演示示例 : 修改 name为csdn的 age值

> db.LABELNET.update({"name":"csdn"},{"$set":{"age":16}},false,true);
WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 })
> db.LABELNET.find();
{ "_id" : ObjectId("55bec40532cbb5faa25c967c"), "name" : "csdn", "age" : 16 }
{ "_id" : ObjectId("55bec43732cbb5faa25c967d"), "name" : "yuan", "age" : "23" }
>

7.3 向集合中的某个文档添加字段 push

> db.LABELNET.update({"name":"yuan"},{$push:{"csdnBlog":"http://blog.youkuaiyun.com/la
blenet"}});
WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 })
> db.LABELNET.find();
{ "_id" : ObjectId("55bec40532cbb5faa25c967c"), "name" : "csdn", "age" : 16 }
{ "_id" : ObjectId("55bec43732cbb5faa25c967d"), "name" : "yuan", "age" : "23", "
csdnBlog" : [ "http://blog.youkuaiyun.com/lablenet" ] }
>

8.删除操作 remove

8.1 基本格式

（1）db.集合名称.remove(where); 条件删除

（2） db.集合名称.remove(); 删除全部记录

（3） db.集合名称.drop(); 删除全部文档（document）

8.2 演示示例：条件删除

> db.LABELNET.remove({"name":"yuan"});
WriteResult({ "nRemoved" : 1 })
> db.LABELNET.find();
{ "_id" : ObjectId("55bec40532cbb5faa25c967c"), "name" : "csdn", "age" : 16 }
>

9. 其他操作

9.1 先准备数据

> db.LABELNET.insert({"name":"yuan","age":23});
WriteResult({ "nInserted" : 1 })
> db.LABELNET.insert({"name":"ming","age":10});
WriteResult({ "nInserted" : 1 })
> db.LABELNET.insert({"name":"zhuo","age":30});
WriteResult({ "nInserted" : 1 })
> db.LABELNET.insert({"name":"hpu","age":30});
WriteResult({ "nInserted" : 1 })
> db.LABELNET.find();
{ "_id" : ObjectId("55bec40532cbb5faa25c967c"), "name" : "csdn", "age" : 16 }
{ "_id" : ObjectId("55beca3932cbb5faa25c967e"), "name" : "yuan", "age" : 23 }
{ "_id" : ObjectId("55beca4632cbb5faa25c967f"), "name" : "ming", "age" : 10 }
{ "_id" : ObjectId("55beca5132cbb5faa25c9680"), "name" : "zhuo", "age" : 30 }
{ "_id" : ObjectId("55beca9f32cbb5faa25c9681"), "name" : "hpu", "age" : 30 }
>

9.1 条件查询 —— > , < , >= ,<=

（1） (>) 大于 - $gt

（2）(<) 小于 - $lt

（3）(>=) 大于等于 - $gte

（4）(<= ) 小于等于 - $lte

> db.LABELNET.find({"age":{"$gt":16}});
{ "_id" : ObjectId("55beca3932cbb5faa25c967e"), "name" : "yuan", "age" : 23 }
{ "_id" : ObjectId("55beca5132cbb5faa25c9680"), "name" : "zhuo", "age" : 30 }
{ "_id" : ObjectId("55beca9f32cbb5faa25c9681"), "name" : "hpu", "age" : 30 }
> db.LABELNET.find({"age":{"$lt":16}});
{ "_id" : ObjectId("55beca4632cbb5faa25c967f"), "name" : "ming", "age" : 10 }
> db.LABELNET.find({"age":{"$gte":16}});
{ "_id" : ObjectId("55bec40532cbb5faa25c967c"), "name" : "csdn", "age" : 16 }
{ "_id" : ObjectId("55beca3932cbb5faa25c967e"), "name" : "yuan", "age" : 23 }
{ "_id" : ObjectId("55beca5132cbb5faa25c9680"), "name" : "zhuo", "age" : 30 }
{ "_id" : ObjectId("55beca9f32cbb5faa25c9681"), "name" : "hpu", "age" : 30 }
> db.LABELNET.find({"age":{"$lte":16}});
{ "_id" : ObjectId("55bec40532cbb5faa25c967c"), "name" : "csdn", "age" : 16 }
{ "_id" : ObjectId("55beca4632cbb5faa25c967f"), "name" : "ming", "age" : 10 }
> db.LABELNET.find({"age":16});
{ "_id" : ObjectId("55bec40532cbb5faa25c967c"), "name" : "csdn", "age" : 16 }
>

9.2 满足条件的条数 count

> db.LABELNET.count({"age":30});
2
>

9.3 得到所有key的value（去掉重复的） distinct

> db.LABELNET.distinct("age");
[ 16, 23, 10, 30 ]
>

9.4 查看集合的数据大小 dataSize ：注意S 大写

> db.LABELNET.dataSize();
560
>

9.5 查看集合状态 stats

> db.LABELNET.stats();
{
        "ns" : "student.LABELNET",
        "count" : 5,
        "size" : 560,
        "avgObjSize" : 112,
        "numExtents" : 1,
        "storageSize" : 8192,
        "lastExtentSize" : 8192,
        "paddingFactor" : 1,
        "paddingFactorNote" : "paddingFactor is unused and unmaintained in 3.0.
It remains hard coded to 1.0 for compatibility only.",
        "userFlags" : 1,
        "capped" : false,
        "nindexes" : 1,
        "totalIndexSize" : 8176,
        "indexSizes" : {
                "_id_" : 8176
        },
        "ok" : 1
}

9.6 分页查询 skip 和 limit （类似于 linq 操作）

> db.LABELNET.find().skip(2).limit(2);
{ "_id" : ObjectId("55beca4632cbb5faa25c967f"), "name" : "ming", "age" : 10 }
{ "_id" : ObjectId("55beca5132cbb5faa25c9680"), "name" : "zhuo", "age" : 30 }
> db.LABELNET.find().skip(0).limit(2);
{ "_id" : ObjectId("55bec40532cbb5faa25c967c"), "name" : "csdn", "age" : 16 }
{ "_id" : ObjectId("55beca3932cbb5faa25c967e"), "name" : "yuan", "age" : 23 }
>

9.7 排序分页 sort , skip , limit

> db.LABELNET.find().sort({"age":1}).skip(0).limit(2);
{ "_id" : ObjectId("55beca4632cbb5faa25c967f"), "name" : "ming", "age" : 10 }
{ "_id" : ObjectId("55bec40532cbb5faa25c967c"), "name" : "csdn", "age" : 16 }
> db.LABELNET.find().sort({"age":1}).skip(2).limit(2);
{ "_id" : ObjectId("55beca3932cbb5faa25c967e"), "name" : "yuan", "age" : 23 }
{ "_id" : ObjectId("55beca5132cbb5faa25c9680"), "name" : "zhuo", "age" : 30 }
>

10.操作函数

10.1 示例：插入100 条数据

> for(var i=0;i<100;i++){var ran=parseInt(i*Math.random());db.LABELNET.insert({"
name":"yuan","age":ran});}
WriteResult({ "nInserted" : 1 })
> db.LABELNET.find();
{ "_id" : ObjectId("55bec40532cbb5faa25c967c"), "name" : "csdn", "age" : 16 }
{ "_id" : ObjectId("55beca3932cbb5faa25c967e"), "name" : "yuan", "age" : 23 }
{ "_id" : ObjectId("55beca4632cbb5faa25c967f"), "name" : "ming", "age" : 10 }
{ "_id" : ObjectId("55beca5132cbb5faa25c9680"), "name" : "zhuo", "age" : 30 }
{ "_id" : ObjectId("55beca9f32cbb5faa25c9681"), "name" : "hpu", "age" : 30 }
{ "_id" : ObjectId("55becfee32cbb5faa25c9682"), "name" : "yuan", "age" : 0 }
{ "_id" : ObjectId("55becfee32cbb5faa25c9683"), "name" : "yuan", "age" : 0 }
{ "_id" : ObjectId("55becfee32cbb5faa25c9684"), "name" : "yuan", "age" : 1 }
{ "_id" : ObjectId("55becfee32cbb5faa25c9685"), "name" : "yuan", "age" : 1 }
{ "_id" : ObjectId("55becfee32cbb5faa25c9686"), "name" : "yuan", "age" : 3 }
{ "_id" : ObjectId("55becfee32cbb5faa25c9687"), "name" : "yuan", "age" : 2 }
{ "_id" : ObjectId("55becfee32cbb5faa25c9688"), "name" : "yuan", "age" : 1 }
{ "_id" : ObjectId("55becfee32cbb5faa25c9689"), "name" : "yuan", "age" : 3 }
{ "_id" : ObjectId("55becfee32cbb5faa25c968a"), "name" : "yuan", "age" : 7 }

10.2 去某个key的值

> var list=db.LABELNET.find(); list.forEach(function(x){print(x.name);});
csdn
yuan
ming
zhuo
hpu
yuan
yuan
yuan
yuan
yuan
yuan
yuan
yuan
yuan
yuan
yuan

10.3 性能分析函数 explain

首先我们查到 age为83的是最后一条，且仅此一条

{ "_id" : ObjectId("55becfee32cbb5faa25c96e5"), "name" : "yuan", "age" : 83 }
> db.LABELNET.count({"age":83});
1
>

后我们查询这个 age为 83 的文档：

> db.LABELNET.count({"age":83});
1
> db.LABELNET.find({"age":83}).explain()  ;
{
        "queryPlanner" : {
                "plannerVersion" : 1,
                "namespace" : "student.LABELNET",
                "indexFilterSet" : false,
                "parsedQuery" : {
                        "age" : {
                                "$eq" : 83
                        }
                },
                "winningPlan" : {
                        "stage" : "COLLSCAN",
                        "filter" : {
                                "age" : {
                                        "$eq" : 83
                                }
                        },
                        "direction" : "forward"
                },
                "rejectedPlans" : [ ]
        },
        "serverInfo" : {
                "host" : "LABELNET",
                "port" : 27017,
                "version" : "3.0.5",
                "gitVersion" : "8bc4ae20708dbb493cb09338d9e7be6698e4a3a3"
        },
        "ok" : 1
}
>

11.索引（非常重要，可提供查询速度）ensureIndex

11.1 添加唯一索引

> db.LABELNET.ensureIndex({"name":1},{"unique":true});
{
        "createdCollectionAutomatically" : false,
        "numIndexesBefore" : 1,
        "errmsg" : "exception: E11000 duplicate key error index: student.LABELNE
T.$name_1 dup key: { : \"yuan\" }",
        "code" : 11000,
        "ok" : 0
}
>

11.2 添加其他索引

> db.LABELNET.ensureIndex({"name":1,"age":1});
{
        "createdCollectionAutomatically" : false,
        "numIndexesBefore" : 1,
        "numIndexesAfter" : 2,
        "ok" : 1
}
>

11.3 查看所有索引

> db.LABELNET.getIndexes();
[
        {
                "v" : 1,
                "key" : {
                        "_id" : 1
                },
                "name" : "_id_",
                "ns" : "student.LABELNET"
        },
        {
                "v" : 1,
                "key" : {
                        "name" : 1,
                        "age" : 1
                },
                "name" : "name_1_age_1",
                "ns" : "student.LABELNET"
        }
]

11.4 删除索引

可能随着业务需求的变化，原先建立的索引可能没有存在的必要了，可能有的人想说没必要就没必要呗，但是请记住，索引会降低CUD这三种操作的性能。

> db.LABELNET.dropIndex("name_1_age_1");
{ "nIndexesWas" : 2, "ok" : 1 }
> db.LABELNET.getIndexes();
[
        {
                "v" : 1,
                "key" : {
                        "_id" : 1
                },
                "name" : "_id_",
                "ns" : "student.LABELNET"
        }
]
>

基本命令就学到这里了，下篇将学习使用 mongodb 的 C#驱动实现增删改查！