笔记 | MongoDB

### 删除文档
#### $drop/$remove
$drop 删除集合的同时删除索引

- db.集合名.drop()

```
# 切换库
> use test_03
switched to db test_03

# 插入集合
> db.student.insert({})
WriteResult({ "nInserted" : 1 })

# 查看集合
> show tables
student

# 查询集合
> db.student.find()
{ "_id" : ObjectId("6029f08077c06d43f849eae3") }

# 删除集合
> db.student.drop()
true

# 查看集合
> show tables
```

remove() 删除文档时不删除索引

- 语法

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

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，如果不设置该参数，或使用默认值 false，则删除所有匹配条件的文档。

删除所有文档

- db.集合名.remove({})

```
# 插入集合
> db.student.insert({"name": "鲁班", "age": 37, "sex": true, "class": 202001, "course": ["python", "web"]})
WriteResult({ "nInserted" : 1 })

# 查询集合
> db.student.find()
{ "_id" : ObjectId("6029f33577c06d43f849eae4"), "name" : "鲁班", "age" : 37, "sex" : true, "class" : 202001, "course" : [ "python", "web" ] }

# 删除所有文档
> db.student.remove({})
WriteResult({ "nRemoved" : 1 })

# 查询集合 没有任何结果
> db.student.find()

# 查看集合
> show tables
student
```

删除与条件匹配的文档
- db.集合名.remove({ 条件 })

示例

- 准备数据

```
# 插入集合
> db.student.insertMany(
...     [
...         {"name": "鲁班", "age": 37, "sex": true, "class": 202001, "course": ["python", "web"]},
...         {"name": "孙策", "age": 27, "sex": true, "class": 202001, "course": ["python", "web"]},
...         {"name": "李信", "age": 24, "sex": true, "class": 202001, "course": ["python", "web"]},
...         {"name": "张飞", "age": 31, "sex": true, "class": 202001, "course": ["python", "web"]},
...         {"name": "后羿", "age": 30, "sex": true, "class": 202001, "course": ["python", "web"]},
...         {"name": "韩信", "age": 22, "sex": true, "class": 202001, "course": ["python", "web"]},
...         {"name": "刘邦", "age": 25, "sex": true, "class": 202001, "course": ["python", "web"]},
...         {"name": "亚瑟", "age": 37, "sex": true, "class": 202001, "course": ["python", "web"]},
...         {"name": "关羽", "age": 24, "sex": true, "class": 202001, "course": ["python", "web"]},
...         {"name": "周瑜", "age": 24, "sex": true, "class": 202001, "course": ["python", "web", "mysql"]},
...         {"name": "吕布", "age": 35, "sex": true, "class": 202001, "course": ["python", "web"]},
...         {"name": "曹操", "age": 43, "sex": true, "class": 202001, "course": ["python", "web"]},
...         {"name": "小乔", "age": 18, "sex": false, "class": 202001, "course": ["python", "web", "mysql"]},
...         {"name": "大乔", "age": 22, "sex": false, "class": 202001, "course": ["python", "web"]},
...         {"name": "嫦娥", "age": 23, "sex": false, "class": 202001, "course": ["python", "web"]},
...     ]
... )
{
	"acknowledged" : true,
	"insertedIds" : [
		ObjectId("6029f81631ce9f8a43308d12"),
		ObjectId("6029f81631ce9f8a43308d13"),
		ObjectId("6029f81631ce9f8a43308d14"),
		ObjectId("6029f81631ce9f8a43308d15"),
		ObjectId("6029f81631ce9f8a43308d16"),
		ObjectId("6029f81631ce9f8a43308d17"),
		ObjectId("6029f81631ce9f8a43308d18"),
		ObjectId("6029f81631ce9f8a43308d19"),
		ObjectId("6029f81631ce9f8a43308d1a"),
		ObjectId("6029f81631ce9f8a43308d1b"),
		ObjectId("6029f81631ce9f8a43308d1c"),
		ObjectId("6029f81631ce9f8a43308d1d"),
		ObjectId("6029f81631ce9f8a43308d1e"),
		ObjectId("6029f81631ce9f8a43308d1f"),
		ObjectId("6029f81631ce9f8a43308d20")
	]
}

# 查看所有集合
> db.student.find()
{ "_id" : ObjectId("6029f81631ce9f8a43308d12"), "name" : "鲁班", "age" : 37, "sex" : true, "class" : 202001, "course" : [ "python", "web" ] }
{ "_id" : ObjectId("6029f81631ce9f8a43308d13"), "name" : "孙策", "age" : 27, "sex" : true, "class" : 202001, "course" : [ "python", "web" ] }
{ "_id" : ObjectId("6029f81631ce9f8a43308d14"), "name" : "李信", "age" : 24, "sex" : true, "class" : 202001, "course" : [ "python", "web" ] }
{ "_id" : ObjectId("6029f81631ce9f8a43308d15"), "name" : "张飞", "age" : 31, "sex" : true, "class" : 202001, "course" : [ "python", "web" ] }
{ "_id" : ObjectId("6029f81631ce9f8a43308d16"), "name" : "后羿", "age" : 30, "sex" : true, "class" : 202001, "course" : [ "python", "web" ] }
{ "_id" : ObjectId("6029f81631ce9f8a43308d17"), "name" : "韩信", "age" : 22, "sex" : true, "class" : 202001, "course" : [ "python", "web" ] }
{ "_id" : ObjectId("6029f81631ce9f8a43308d18"), "name" : "刘邦", "age" : 25, "sex" : true, "class" : 202001, "course" : [ "python", "web" ] }
{ "_id" : ObjectId("6029f81631ce9f8a43308d19"), "name" : "亚瑟", "age" : 37, "sex" : true, "class" : 202001, "course" : [ "python", "web" ] }
{ "_id" : ObjectId("6029f81631ce9f8a43308d1a"), "name" : "关羽", "age" : 24, "sex" : true, "class" : 202001, "course" : [ "python", "web" ] }
{ "_id" : ObjectId("6029f81631ce9f8a43308d1b"), "name" : "周瑜", "age" : 24, "sex" : true, "class" : 202001, "course" : [ "python", "web", "mysql" ] }
{ "_id" : ObjectId("6029f81631ce9f8a43308d1c"), "name" : "吕布", "age" : 35, "sex" : true, "class" : 202001, "course" : [ "python", "web" ] }
{ "_id" : ObjectId("6029f81631ce9f8a43308d1d"), "name" : "曹操", "age" : 43, "sex" : true, "class" : 202001, "course" : [ "python", "web" ] }
{ "_id" : ObjectId("6029f81631ce9f8a43308d1e"), "name" : "小乔", "age" : 18, "sex" : false, "class" : 202001, "course" : [ "python", "web", "mysql" ] }
{ "_id" : ObjectId("6029f81631ce9f8a43308d1f"), "name" : "大乔", "age" : 22, "sex" : false, "class" : 202001, "course" : [ "python", "web" ] }
{ "_id" : ObjectId("6029f81631ce9f8a43308d20"), "name" : "嫦娥", "age" : 23, "sex" : false, "class" : 202001, "course" : [ "python", "web" ] }
```

- 删除条件匹配的集合

```
# 删除条件匹配的集合
> db.student.remove({"name" : "鲁班"})
WriteResult({ "nRemoved" : 1 })

# 确认数据
> db.student.find()
{ "_id" : ObjectId("6029f81631ce9f8a43308d13"), "name" : "孙策", "age" : 27, "sex" : true, "class" : 202001, "course" : [ "python", "web" ] }
{ "_id" : ObjectId("6029f81631ce9f8a43308d14"), "name" : "李信", "age" : 24, "sex" : true, "class" : 202001, "course" : [ "python", "web" ] }
{ "_id" : ObjectId("6029f81631ce9f8a43308d15"), "name" : "张飞", "age" : 31, "sex" : true, "class" : 202001, "course" : [ "python", "web" ] }
{ "_id" : ObjectId("6029f81631ce9f8a43308d16"), "name" : "后羿", "age" : 30, "sex" : true, "class" : 202001, "course" : [ "python", "web" ] }
{ "_id" : ObjectId("6029f81631ce9f8a43308d17"), "name" : "韩信", "age" : 22, "sex" : true, "class" : 202001, "course" : [ "python", "web" ] }
{ "_id" : ObjectId("6029f81631ce9f8a43308d18"), "name" : "刘邦", "age" : 25, "sex" : true, "class" : 202001, "course" : [ "python", "web" ] }
{ "_id" : ObjectId("6029f81631ce9f8a43308d19"), "name" : "亚瑟", "age" : 37, "sex" : true, "class" : 202001, "course" : [ "python", "web" ] }
{ "_id" : ObjectId("6029f81631ce9f8a43308d1a"), "name" : "关羽", "age" : 24, "sex" : true, "class" : 202001, "course" : [ "python", "web" ] }
{ "_id" : ObjectId("6029f81631ce9f8a43308d1b"), "name" : "周瑜", "age" : 24, "sex" : true, "class" : 202001, "course" : [ "python", "web", "mysql" ] }
{ "_id" : ObjectId("6029f81631ce9f8a43308d1c"), "name" : "吕布", "age" : 35, "sex" : true, "class" : 202001, "course" : [ "python", "web" ] }
{ "_id" : ObjectId("6029f81631ce9f8a43308d1d"), "name" : "曹操", "age" : 43, "sex" : true, "class" : 202001, "course" : [ "python", "web" ] }
{ "_id" : ObjectId("6029f81631ce9f8a43308d1e"), "name" : "小乔", "age" : 18, "sex" : false, "class" : 202001, "course" : [ "python", "web", "mysql" ] }
{ "_id" : ObjectId("6029f81631ce9f8a43308d1f"), "name" : "大乔", "age" : 22, "sex" : false, "class" : 202001, "course" : [ "python", "web" ] }
{ "_id" : ObjectId("6029f81631ce9f8a43308d20"), "name" : "嫦娥", "age" : 23, "sex" : false, "class" : 202001, "course" : [ "python", "web" ] }
```

- 默认匹配所有字段

```
# 删除集合，默认匹配所有字段
> db.student.remove({"age" : 24,})
WriteResult({ "nRemoved" : 3 })

# 确认结果
> db.student.find()
{ "_id" : ObjectId("6029f81631ce9f8a43308d13"), "name" : "孙策", "age" : 27, "sex" : true, "class" : 202001, "course" : [ "python", "web" ] }
{ "_id" : ObjectId("6029f81631ce9f8a43308d15"), "name" : "张飞", "age" : 31, "sex" : true, "class" : 202001, "course" : [ "python", "web" ] }
{ "_id" : ObjectId("6029f81631ce9f8a43308d16"), "name" : "后羿", "age" : 30, "sex" : true, "class" : 202001, "course" : [ "python", "web" ] }
{ "_id" : ObjectId("6029f81631ce9f8a43308d17"), "name" : "韩信", "age" : 22, "sex" : true, "class" : 202001, "course" : [ "python", "web" ] }
{ "_id" : ObjectId("6029f81631ce9f8a43308d18"), "name" : "刘邦", "age" : 25, "sex" : true, "class" : 202001, "course" : [ "python", "web" ] }
{ "_id" : ObjectId("6029f81631ce9f8a43308d19"), "name" : "亚瑟", "age" : 37, "sex" : true, "class" : 202001, "course" : [ "python", "web" ] }
{ "_id" : ObjectId("6029f81631ce9f8a43308d1c"), "name" : "吕布", "age" : 35, "sex" : true, "class" : 202001, "course" : [ "python", "web" ] }
{ "_id" : ObjectId("6029f81631ce9f8a43308d1d"), "name" : "曹操", "age" : 43, "sex" : true, "class" : 202001, "course" : [ "python", "web" ] }
{ "_id" : ObjectId("6029f81631ce9f8a43308d1e"), "name" : "小乔", "age" : 18, "sex" : false, "class" : 202001, "course" : [ "python", "web", "mysql" ] }
{ "_id" : ObjectId("6029f81631ce9f8a43308d1f"), "name" : "大乔", "age" : 22, "sex" : false, "class" : 202001, "course" : [ "python", "web" ] }
{ "_id" : ObjectId("6029f81631ce9f8a43308d20"), "name" : "嫦娥", "age" : 23, "sex" : false, "class" : 202001, "course" : [ "python", "web" ] }
```

- 只删除一条数据

```
# 只删除一条数据
> db.student.remove({"sex" : true}, {justOne: 1})
WriteResult({ "nRemoved" : 1 })

# 确认结果
> db.student.find()
{ "_id" : ObjectId("6029f81631ce9f8a43308d15"), "name" : "张飞", "age" : 31, "sex" : true, "class" : 202001, "course" : [ "python", "web" ] }
{ "_id" : ObjectId("6029f81631ce9f8a43308d16"), "name" : "后羿", "age" : 30, "sex" : true, "class" : 202001, "course" : [ "python", "web" ] }
{ "_id" : ObjectId("6029f81631ce9f8a43308d17"), "name" : "韩信", "age" : 22, "sex" : true, "class" : 202001, "course" : [ "python", "web" ] }
{ "_id" : ObjectId("6029f81631ce9f8a43308d18"), "name" : "刘邦", "age" : 25, "sex" : true, "class" : 202001, "course" : [ "python", "web" ] }
{ "_id" : ObjectId("6029f81631ce9f8a43308d19"), "name" : "亚瑟", "age" : 37, "sex" : true, "class" : 202001, "course" : [ "python", "web" ] }
{ "_id" : ObjectId("6029f81631ce9f8a43308d1c"), "name" : "吕布", "age" : 35, "sex" : true, "class" : 202001, "course" : [ "python", "web" ] }
{ "_id" : ObjectId("6029f81631ce9f8a43308d1d"), "name" : "曹操", "age" : 43, "sex" : true, "class" : 202001, "course" : [ "python", "web" ] }
{ "_id" : ObjectId("6029f81631ce9f8a43308d1e"), "name" : "小乔", "age" : 18, "sex" : false, "class" : 202001, "course" : [ "python", "web", "mysql" ] }
{ "_id" : ObjectId("6029f81631ce9f8a43308d1f"), "name" : "大乔", "age" : 22, "sex" : false, "class" : 202001, "course" : [ "python", "web" ] }
{ "_id" : ObjectId("6029f81631ce9f8a43308d20"), "name" : "嫦娥", "age" : 23, "sex" : false, "class" : 202001, "course" : [ "python", "web" ] }
```

#### $deleteOne/$deleteMany
deleteOne({条件})
- 只删除匹配条件的一条数据

```
# 只删除匹配条件的一条数据
> db.student.deleteOne({"sex" : true})
{ "acknowledged" : true, "deletedCount" : 1 }

# 确认结果
> db.student.find()
{ "_id" : ObjectId("6029f81631ce9f8a43308d16"), "name" : "后羿", "age" : 30, "sex" : true, "class" : 202001, "course" : [ "python", "web" ] }
{ "_id" : ObjectId("6029f81631ce9f8a43308d17"), "name" : "韩信", "age" : 22, "sex" : true, "class" : 202001, "course" : [ "python", "web" ] }
{ "_id" : ObjectId("6029f81631ce9f8a43308d18"), "name" : "刘邦", "age" : 25, "sex" : true, "class" : 202001, "course" : [ "python", "web" ] }
{ "_id" : ObjectId("6029f81631ce9f8a43308d19"), "name" : "亚瑟", "age" : 37, "sex" : true, "class" : 202001, "course" : [ "python", "web" ] }
{ "_id" : ObjectId("6029f81631ce9f8a43308d1c"), "name" : "吕布", "age" : 35, "sex" : true, "class" : 202001, "course" : [ "python", "web" ] }
{ "_id" : ObjectId("6029f81631ce9f8a43308d1d"), "name" : "曹操", "age" : 43, "sex" : true, "class" : 202001, "course" : [ "python", "web" ] }
{ "_id" : ObjectId("6029f81631ce9f8a43308d1e"), "name" : "小乔", "age" : 18, "sex" : false, "class" : 202001, "course" : [ "python", "web", "mysql" ] }
{ "_id" : ObjectId("6029f81631ce9f8a43308d1f"), "name" : "大乔", "age" : 22, "sex" : false, "class" : 202001, "course" : [ "python", "web" ] }
{ "_id" : ObjectId("6029f81631ce9f8a43308d20"), "name" : "嫦娥", "age" : 23, "sex" : false, "class" : 202001, "course" : [ "python", "web" ] }
```

deleteMany({条件})
- 删除匹配条件的所有文档

```
# 删除大于24岁的所有学生
> db.student.deleteMany({"age": {$gt: 24}})
{ "acknowledged" : true, "deletedCount" : 5 }

# 确认结果
> db.student.find()
{ "_id" : ObjectId("6029f81631ce9f8a43308d17"), "name" : "韩信", "age" : 22, "sex" : true, "class" : 202001, "course" : [ "python", "web" ] }
{ "_id" : ObjectId("6029f81631ce9f8a43308d1e"), "name" : "小乔", "age" : 18, "sex" : false, "class" : 202001, "course" : [ "python", "web", "mysql" ] }
{ "_id" : ObjectId("6029f81631ce9f8a43308d1f"), "name" : "大乔", "age" : 22, "sex" : false, "class" : 202001, "course" : [ "python", "web" ] }
{ "_id" : ObjectId("6029f81631ce9f8a43308d20"), "name" : "嫦娥", "age" : 23, "sex" : false, "class" : 202001, "course" : [ "python", "web" ] }
```

deleteMany({})
- 删除所有文档

```
# 删除所有文档
> db.student.deleteMany({})
{ "acknowledged" : true, "deletedCount" : 4 }

# 确认结果
> db.student.find()

# 查看集合
> show tables
student
```

晓松

MongoDB 删除文档

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晓松

MongoDB 删除文档 MongoDB 文档常用删除方法

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