mongodb-基础-update-remove

时间:2022-05-04
本文章向大家介绍mongodb-基础-update-remove,主要内容包括3.save() 方法、更多实例、3.save() 方法、更多实例、基本概念、基础应用、原理机制和需要注意的事项等,并结合实例形式分析了其使用技巧,希望通过本文能帮助到大家理解应用这部分内容。

1.一些操作

collection重命名:

> db.post.renameCollection('foo')
{ "ok" : 1 }
> show collections
foo

2.update

语法格式:

db.collection.update(
  <query>,
  <update>,
  {
    upsert: <boolean>,
    multi: <boolean>,
    writeConcern: <document>
  }) 

参数说明:

  • query : update的查询条件,类似sql update查询内where后面的。
  • update : 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 : 可选,这个参数的意思是,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 : 可选,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。
  • writeConcern :可选,抛出异常的级别。

示例:

>db.foo.insert([
     {"title":"MongoDB Overview"},
     {"title":"NoSQL Overview"},
     {"title":"Test Update"}
])

> db.foo.find()
{ "_id" : ObjectId("577f11860fe1ae602eda933a"), "title" : "MongoDB Overview" }
{ "_id" : ObjectId("577f11860fe1ae602eda933b"), "title" : "NoSQL Overview" }
{ "_id" : ObjectId("577f11860fe1ae602eda933c"), "title" : "Test Update" }
>
> db.foo.update(
... {'title':'MongoDB Overview'},
... {$set:{'title':'New MongoDB Overview'}}
... )
WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 })
>
> db.foo.find()
{ "_id" : ObjectId("577f11860fe1ae602eda933a"), "title" : "New MongoDB Overview"
 }
{ "_id" : ObjectId("577f11860fe1ae602eda933b"), "title" : "NoSQL Overview" }
{ "_id" : ObjectId("577f11860fe1ae602eda933c"), "title" : "Test Update" }
>

测试更新多个:

# 初始化数据
> db.post.insert(
[
{'username':'Ryan','age':18,'sex':0,'hobby':'read'},
{'username':'Leslie','age':18,'sex':1,'hobby':'watch TV'},
{'username':'Tom','age':20,'sex':0,'hobby':'eat 老鼠'}
])
BulkWriteResult({
        "writeErrors" : [ ],
        "writeConcernErrors" : [ ],
        "nInserted" : 3,
        "nUpserted" : 0,
        "nMatched" : 0,
        "nModified" : 0,
        "nRemoved" : 0,
        "upserted" : [ ]
})

> db.post.find().pretty()
{
        "_id" : ObjectId("577f145a0fe1ae602eda933d"),
        "username" : "Ryan",
        "age" : 18,
        "sex" : 0,
        "hobby" : "read"
}
{
        "_id" : ObjectId("577f145a0fe1ae602eda933e"),
        "username" : "Leslie",
        "age" : 18,
        "sex" : 1,
        "hobby" : "watch TV"
}
{
        "_id" : ObjectId("577f145a0fe1ae602eda933f"),
        "username" : "Tom",
        "age" : 20,
        "sex" : 0,
        "hobby" : "eat 老鼠"
}

结果发现,这种更新只能更新匹配的第一条记录:

#更新age=18的为age=20
> db.post.update(
... {'age':18},
... {$set:{'age':20}}
... )
WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 })
> db.post.find().pretty()
{
        "_id" : ObjectId("577f145a0fe1ae602eda933d"),
        "username" : "Ryan",
        "age" : 20,
        "sex" : 0,
        "hobby" : "read"
}
{
        "_id" : ObjectId("577f145a0fe1ae602eda933e"),
        "username" : "Leslie",
        "age" : 18,
        "sex" : 1,
        "hobby" : "watch TV"
}
{
        "_id" : ObjectId("577f145a0fe1ae602eda933f"),
        "username" : "Tom",
        "age" : 20,
        "sex" : 0,
        "hobby" : "eat 老鼠"
}

如果想要更新符合条件的所有的记录,需要设置multi:true:

# 更新age=20 为 age=22
> db.post.update( {'age':20}, {$set:{'age':22}},{multi:true} )
WriteResult({ "nMatched" : 2, "nUpserted" : 0, "nModified" : 2 })
> db.post.find().pretty()
{
        "_id" : ObjectId("577f145a0fe1ae602eda933d"),
        "username" : "Ryan",
        "age" : 22,
        "sex" : 0,
        "hobby" : "read"
}
{
        "_id" : ObjectId("577f145a0fe1ae602eda933e"),
        "username" : "Leslie",
        "age" : 18,
        "sex" : 1,
        "hobby" : "watch TV"
}
{
        "_id" : ObjectId("577f145a0fe1ae602eda933f"),
        "username" : "Tom",
        "age" : 22,
        "sex" : 0,
        "hobby" : "eat 老鼠"
}

3.save() 方法

save() 方法通过传入的文档来替换已有文档。语法格式如下:

db.collection.save(<document>,{
     writeConcern:<document>})

参数说明:

  • document : 文档数据。
  • writeConcern :可选,抛出异常的级别

如果传入的文档中含有_id,并且_id的值是数据库中已经存在的,则替换该条记录。

如果传入的文档中含有_id,并且_id的值在数据库中不存在,则相当于insert,插入一条数据。

如果传入的文档中没有_id,则相当于insert,插入一条数据。

示例:

数据库中元数据:

> db.post.find().pretty()
{
        "_id" : ObjectId("577f145a0fe1ae602eda933d"),
        "username" : "Ryan",
        "age" : 22,
        "sex" : 0,
        "hobby" : "read"
}
{
        "_id" : ObjectId("577f145a0fe1ae602eda933e"),
        "username" : "Leslie",
        "age" : 18,
        "sex" : 1,
        "hobby" : "watch TV"
}
{
        "_id" : ObjectId("577f145a0fe1ae602eda933f"),
        "username" : "Tom",
        "age" : 22,
        "sex" : 0,
        "hobby" : "eat 老鼠"
}

替换最后一条记录:

> db.post.save({
... "_id" : ObjectId("577f145a0fe1ae602eda933f"),
... "username":"Jack",
... "age":30,
... sex:1,
... hobby:'running'
... })
WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 })
> db.post.find().pretty()
{
        "_id" : ObjectId("577f145a0fe1ae602eda933d"),
        "username" : "Ryan",
        "age" : 22,
        "sex" : 0,
        "hobby" : "read"
}
{
        "_id" : ObjectId("577f145a0fe1ae602eda933e"),
        "username" : "Leslie",
        "age" : 18,
        "sex" : 1,
        "hobby" : "watch TV"
}
{
        "_id" : ObjectId("577f145a0fe1ae602eda933f"),
        "username" : "Jack",
        "age" : 30,
        "sex" : 1,
        "hobby" : "running"
}

如果没有指定_id,相当于insert:

> db.post.save({ "username":"Mary", "age":28, sex:0, hobby:'sleep' })
WriteResult({ "nInserted" : 1 })
> db.post.find().pretty()
{
        "_id" : ObjectId("577f145a0fe1ae602eda933d"),
        "username" : "Ryan",
        "age" : 22,
        "sex" : 0,
        "hobby" : "read"
}
{
        "_id" : ObjectId("577f145a0fe1ae602eda933e"),
        "username" : "Leslie",
        "age" : 18,
        "sex" : 1,
        "hobby" : "watch TV"
}
{
        "_id" : ObjectId("577f145a0fe1ae602eda933f"),
        "username" : "Jack",
        "age" : 30,
        "sex" : 1,
        "hobby" : "running"
}
{
        "_id" : ObjectId("577f1fd30fe1ae602eda9340"),
        "username" : "Mary",
        "age" : 28,
        "sex" : 0,
        "hobby" : "sleep"
}

如果指定了_id,但没有数据库匹配该id,则相当于insert,插入一条数据:

> db.post.save({ "_id" : 123123, "username":"Jack", "age":30, sex:1, hobby:'runn
ing' })
WriteResult({ "nMatched" : 0, "nUpserted" : 1, "nModified" : 0, "_id" : 123123 }
)
> db.post.find().pretty()
{
        "_id" : ObjectId("577f145a0fe1ae602eda933d"),
        "username" : "Ryan",
        "age" : 22,
        "sex" : 0,
        "hobby" : "read"
}
{
        "_id" : ObjectId("577f145a0fe1ae602eda933e"),
        "username" : "Leslie",
        "age" : 18,
        "sex" : 1,
        "hobby" : "watch TV"
}
{
        "_id" : ObjectId("577f145a0fe1ae602eda933f"),
        "username" : "Jack",
        "age" : 30,
        "sex" : 1,
        "hobby" : "running"
}
{
        "_id" : ObjectId("577f1fd30fe1ae602eda9340"),
        "username" : "Mary",
        "age" : 28,
        "sex" : 0,
        "hobby" : "sleep"
}
{
        "_id" : 123123,
        "username" : "Jack",
        "age" : 30,
        "sex" : 1,
        "hobby" : "running"
}

更多实例

只更新第一条记录:

db.col.update( { "count" : { $gt : 1 } } , { $set : { "test2" : "OK"} } );

全部更新:

db.col.update( { "count" : { $gt : 3 } } , { $set : { "test2" : "OK"} },false,true );

只添加第一条:

db.col.update( { "count" : { $gt : 4 } } , { $set : { "test5" : "OK"} },true,false );

全部添加加进去:

db.col.update( { "count" : { $gt : 5 } } , { $set : { "test5" : "OK"} },true,true );

全部更新:

db.col.update( { "count" : { $gt : 15 } } , { $inc : { "count" : 1} },false,true );

只更新第一条记录:

db.col.update( { "count" : { $gt : 10 } } , { $inc : { "count" : 1} },false,false );

4.remove

语法

remove() 方法的基本语法格式如下所示:

db.collection.remove(<query>,<justOne>)

如果你的 MongoDB 是 2.6 版本以后的,语法格式如下:

db.collection.remove(<query>,{
     justOne:<boolean>,
     writeConcern:<document>})

参数说明:

  • query :(可选)删除的文档的条件。
  • justOne : (可选)如果设为 true 或 1,则只删除一个文档。
  • writeConcern :(可选)抛出异常的级别。

示例:

首先插入两条数据:

> db.col.insert({
... title:'MongoDB Teach',
... by:'菜鸟教程',
... url:'http://www.runoob.com',
... tags:['mongodb','database','NoSQL'],
... likes:100
... })
WriteResult({ "nInserted" : 1 })
> db.col.insert({ title:'MongoDB Teach', by:'菜鸟教程', url:'http://www.runoob.c
om', tags:['mongodb','database','NoSQL'], likes:100 })
WriteResult({ "nInserted" : 1 })
>
>
> db.col.find()
{ "_id" : ObjectId("577f52430fe1ae602eda9341"), "title" : "MongoDB Teach", "by"
: "菜鸟教程", "url" : "http://www.runoob.com", "tags" : [ "mongodb", "database",
 "NoSQL" ], "likes" : 100 }
{ "_id" : ObjectId("577f52460fe1ae602eda9342"), "title" : "MongoDB Teach", "by"
: "菜鸟教程", "url" : "http://www.runoob.com", "tags" : [ "mongodb", "database",
 "NoSQL" ], "likes" : 100 }

然后,删除:

> db.col.remove({'title':'MongoDB Teach'})
WriteResult({ "nRemoved" : 2 })

可以看到,两条都删除了,即:满足条件的都删除。因此,如果想清空表:

> db.col.remove({})

相当于 SQL 的 truncate 命令.

1.一些操作

collection重命名:

> db.post.renameCollection('foo')
{ "ok" : 1 }
> show collections
foo

2.update

语法格式:

db.collection.update(
  <query>,
  <update>,
  {
    upsert: <boolean>,
    multi: <boolean>,
    writeConcern: <document>
  })

参数说明:

  • query : update的查询条件,类似sql update查询内where后面的。
  • update : 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 : 可选,这个参数的意思是,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 : 可选,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。
  • writeConcern :可选,抛出异常的级别。

示例:

>db.foo.insert([
     {"title":"MongoDB Overview"},
     {"title":"NoSQL Overview"},
     {"title":"Test Update"}
])
> db.foo.find()
{ "_id" : ObjectId("577f11860fe1ae602eda933a"), "title" : "MongoDB Overview" }
{ "_id" : ObjectId("577f11860fe1ae602eda933b"), "title" : "NoSQL Overview" }
{ "_id" : ObjectId("577f11860fe1ae602eda933c"), "title" : "Test Update" }
>
> db.foo.update(
... {'title':'MongoDB Overview'},
... {$set:{'title':'New MongoDB Overview'}}
... )
WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 })
>
> db.foo.find()
{ "_id" : ObjectId("577f11860fe1ae602eda933a"), "title" : "New MongoDB Overview"
 }
{ "_id" : ObjectId("577f11860fe1ae602eda933b"), "title" : "NoSQL Overview" }
{ "_id" : ObjectId("577f11860fe1ae602eda933c"), "title" : "Test Update" }
>

测试更新多个:

# 初始化数据

> db.post.insert(
[
{'username':'Ryan','age':18,'sex':0,'hobby':'read'},
{'username':'Leslie','age':18,'sex':1,'hobby':'watch TV'},
{'username':'Tom','age':20,'sex':0,'hobby':'eat 老鼠'}
])
BulkWriteResult({
        "writeErrors" : [ ],
        "writeConcernErrors" : [ ],
        "nInserted" : 3,
        "nUpserted" : 0,
        "nMatched" : 0,
        "nModified" : 0,
        "nRemoved" : 0,
        "upserted" : [ ]
})
> db.post.find().pretty()
{
        "_id" : ObjectId("577f145a0fe1ae602eda933d"),
        "username" : "Ryan",
        "age" : 18,
        "sex" : 0,
        "hobby" : "read"
}
{
        "_id" : ObjectId("577f145a0fe1ae602eda933e"),
        "username" : "Leslie",
        "age" : 18,
        "sex" : 1,
        "hobby" : "watch TV"
}
{
        "_id" : ObjectId("577f145a0fe1ae602eda933f"),
        "username" : "Tom",
        "age" : 20,
        "sex" : 0,
        "hobby" : "eat 老鼠"
}

结果发现,这种更新只能更新匹配的第一条记录:

#更新age=18的为age=20
> db.post.update(
... {'age':18},
... {$set:{'age':20}}
... )
WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 })
> db.post.find().pretty()
{
        "_id" : ObjectId("577f145a0fe1ae602eda933d"),
        "username" : "Ryan",
        "age" : 20,
        "sex" : 0,
        "hobby" : "read"
}
{
        "_id" : ObjectId("577f145a0fe1ae602eda933e"),
        "username" : "Leslie",
        "age" : 18,
        "sex" : 1,
        "hobby" : "watch TV"
}
{
        "_id" : ObjectId("577f145a0fe1ae602eda933f"),
        "username" : "Tom",
        "age" : 20,
        "sex" : 0,
        "hobby" : "eat 老鼠"
}

如果想要更新符合条件的所有的记录,需要设置multi:true:

# 更新age=20 为 age=22
> db.post.update( {'age':20}, {$set:{'age':22}},{multi:true} )
WriteResult({ "nMatched" : 2, "nUpserted" : 0, "nModified" : 2 })
> db.post.find().pretty()
{
        "_id" : ObjectId("577f145a0fe1ae602eda933d"),
        "username" : "Ryan",
        "age" : 22,
        "sex" : 0,
        "hobby" : "read"
}
{
        "_id" : ObjectId("577f145a0fe1ae602eda933e"),
        "username" : "Leslie",
        "age" : 18,
        "sex" : 1,
        "hobby" : "watch TV"
}
{
        "_id" : ObjectId("577f145a0fe1ae602eda933f"),
        "username" : "Tom",
        "age" : 22,
        "sex" : 0,
        "hobby" : "eat 老鼠"
}

3.save() 方法

save() 方法通过传入的文档来替换已有文档。语法格式如下:

db.collection.save(<document>,{
     writeConcern:<document>})

参数说明:

  • document : 文档数据。
  • writeConcern :可选,抛出异常的级别

如果传入的文档中含有_id,并且_id的值是数据库中已经存在的,则替换该条记录。

如果传入的文档中含有_id,并且_id的值在数据库中不存在,则相当于insert,插入一条数据。

如果传入的文档中没有_id,则相当于insert,插入一条数据。

示例:

数据库中元数据:

> db.post.find().pretty()
{
        "_id" : ObjectId("577f145a0fe1ae602eda933d"),
        "username" : "Ryan",
        "age" : 22,
        "sex" : 0,
        "hobby" : "read"
}
{
        "_id" : ObjectId("577f145a0fe1ae602eda933e"),
        "username" : "Leslie",
        "age" : 18,
        "sex" : 1,
        "hobby" : "watch TV"
}
{
        "_id" : ObjectId("577f145a0fe1ae602eda933f"),
        "username" : "Tom",
        "age" : 22,
        "sex" : 0,
        "hobby" : "eat 老鼠"
}

替换最后一条记录:

> db.post.save({
... "_id" : ObjectId("577f145a0fe1ae602eda933f"),
... "username":"Jack",
... "age":30,
... sex:1,
... hobby:'running'
... })
WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 })
> db.post.find().pretty()
{
        "_id" : ObjectId("577f145a0fe1ae602eda933d"),
        "username" : "Ryan",
        "age" : 22,
        "sex" : 0,
        "hobby" : "read"
}
{
        "_id" : ObjectId("577f145a0fe1ae602eda933e"),
        "username" : "Leslie",
        "age" : 18,
        "sex" : 1,
        "hobby" : "watch TV"
}
{
        "_id" : ObjectId("577f145a0fe1ae602eda933f"),
        "username" : "Jack",
        "age" : 30,
        "sex" : 1,
        "hobby" : "running"
}

如果没有指定_id,相当于insert:

> db.post.save({ "username":"Mary", "age":28, sex:0, hobby:'sleep' })
WriteResult({ "nInserted" : 1 })
> db.post.find().pretty()
{
        "_id" : ObjectId("577f145a0fe1ae602eda933d"),
        "username" : "Ryan",
        "age" : 22,
        "sex" : 0,
        "hobby" : "read"
}
{
        "_id" : ObjectId("577f145a0fe1ae602eda933e"),
        "username" : "Leslie",
        "age" : 18,
        "sex" : 1,
        "hobby" : "watch TV"
}
{
        "_id" : ObjectId("577f145a0fe1ae602eda933f"),
        "username" : "Jack",
        "age" : 30,
        "sex" : 1,
        "hobby" : "running"
}
{
        "_id" : ObjectId("577f1fd30fe1ae602eda9340"),
        "username" : "Mary",
        "age" : 28,
        "sex" : 0,
        "hobby" : "sleep"
}

如果指定了_id,但没有数据库匹配该id,则相当于insert,插入一条数据:

> db.post.save({ "_id" : 123123, "username":"Jack", "age":30, sex:1, hobby:'runn
ing' })
WriteResult({ "nMatched" : 0, "nUpserted" : 1, "nModified" : 0, "_id" : 123123 }
)
> db.post.find().pretty()
{
        "_id" : ObjectId("577f145a0fe1ae602eda933d"),
        "username" : "Ryan",
        "age" : 22,
        "sex" : 0,
        "hobby" : "read"
}
{
        "_id" : ObjectId("577f145a0fe1ae602eda933e"),
        "username" : "Leslie",
        "age" : 18,
        "sex" : 1,
        "hobby" : "watch TV"
}
{
        "_id" : ObjectId("577f145a0fe1ae602eda933f"),
        "username" : "Jack",
        "age" : 30,
        "sex" : 1,
        "hobby" : "running"
}
{
        "_id" : ObjectId("577f1fd30fe1ae602eda9340"),
        "username" : "Mary",
        "age" : 28,
        "sex" : 0,
        "hobby" : "sleep"
}
{
        "_id" : 123123,
        "username" : "Jack",
        "age" : 30,
        "sex" : 1,
        "hobby" : "running"
}

更多实例

只更新第一条记录:

db.col.update( { "count" : { $gt : 1 } } , { $set : { "test2" : "OK"} } );

全部更新:

db.col.update( { "count" : { $gt : 3 } } , { $set : { "test2" : "OK"} },false,true );

只添加第一条:

db.col.update( { "count" : { $gt : 4 } } , { $set : { "test5" : "OK"} },true,false );

全部添加加进去:

db.col.update( { "count" : { $gt : 5 } } , { $set : { "test5" : "OK"} },true,true );

全部更新:

db.col.update( { "count" : { $gt : 15 } } , { $inc : { "count" : 1} },false,true );

只更新第一条记录:

db.col.update( { "count" : { $gt : 10 } } , { $inc : { "count" : 1} },false,false );

4.remove

语法

remove() 方法的基本语法格式如下所示:

db.collection.remove(<query>,<justOne>)

如果你的 MongoDB 是 2.6 版本以后的,语法格式如下:

db.collection.remove(<query>,{
     justOne:<boolean>,
     writeConcern:<document>})

参数说明:

  • query :(可选)删除的文档的条件。
  • justOne : (可选)如果设为 true 或 1,则只删除一个文档。
  • writeConcern :(可选)抛出异常的级别。

示例:

首先插入两条数据:

> db.col.insert({
... title:'MongoDB Teach',
... by:'菜鸟教程',
... url:'http://www.runoob.com',
... tags:['mongodb','database','NoSQL'],
... likes:100
... })
WriteResult({ "nInserted" : 1 })
> db.col.insert({ title:'MongoDB Teach', by:'菜鸟教程', url:'http://www.runoob.c
om', tags:['mongodb','database','NoSQL'], likes:100 })
WriteResult({ "nInserted" : 1 })
>
>
> db.col.find()
{ "_id" : ObjectId("577f52430fe1ae602eda9341"), "title" : "MongoDB Teach", "by"
: "菜鸟教程", "url" : "http://www.runoob.com", "tags" : [ "mongodb", "database",
 "NoSQL" ], "likes" : 100 }
{ "_id" : ObjectId("577f52460fe1ae602eda9342"), "title" : "MongoDB Teach", "by"
: "菜鸟教程", "url" : "http://www.runoob.com", "tags" : [ "mongodb", "database",
 "NoSQL" ], "likes" : 100 }

然后,删除:

> db.col.remove({'title':'MongoDB Teach'})
WriteResult({ "nRemoved" : 2 })

可以看到,两条都删除了,即:满足条件的都删除。因此,如果想清空表:

> db.col.remove({})

相当于 SQL 的 truncate 命令.

from:http://www.runoob.com/mongodb/mongodb-update.html