【MongoDB】修改文档/更新文档

update() 方法

update() 方法用于更新已存在的文档。语法格式如下：

db.集合名.update(query,update[,upsert,multi])

参数：
query：必要参数，代表原有的数据，可使用如下参数指定条件范围：

• 大于：$gt
• 小于：$lt
• 等于：$eq
• 不等于：$ne
• 大于等于：$gte
• 小于等于：$lte

update：必要参数，代表更新后的数据，可使用如下参数指定修改方式：

• $set：设置值
• $rename:重命名
• $unset:删除
• $inc：增加值

upsert：可选参数，如果不存在update记录，是否插入更新的数据，是一个布尔值

• true：插入
• false：不插入（默认）

multi：可选参数，是否将查询出来的数据全部更新，是一个布尔值

• true：代表全部更新
• false：代表只更新一条（默认）

添加数据

db.student.insert([
{"name":"zs","age":20,"class":1},
{"name":"aaa","age":21,"class":1},
{"name":"bbb","age":20,"class":2},
{"name":"ccc","age":21,"class":1},
{"name":"ddd","age":21,"class":2}])

修改指定数据

将name=‘zs’的数据改为’000’

> db.student.update({"name":"zs"},{"name":"000"})
WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 })
> db.student.find()
{ "_id" : ObjectId("6239db19f77d1e577d985cc3"), "name" : "000" }
{ "_id" : ObjectId("6239db19f77d1e577d985cc4"), "name" : "aaa", "age" : 21, "class" : 1 }
{ "_id" : ObjectId("6239db19f77d1e577d985cc5"), "name" : "bbb", "age" : 20, "class" : 2 }
{ "_id" : ObjectId("6239db19f77d1e577d985cc6"), "name" : "ccc", "age" : 21, "class" : 1 }
{ "_id" : ObjectId("6239db19f77d1e577d985cc7"), "name" : "ddd", "age" : 21, "class" : 2 }

使用这种方式传参会改变整个数据，想要只修改一项可使用下面的方法

> db.student.update({"name":"zs"},{"$set":{"name":"000"}})
WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 })
> db.student.find()
{ "_id" : ObjectId("6239db19f77d1e577d985cc3"), "name" : "000", "age" : 20, "class" : 1 }
{ "_id" : ObjectId("6239db19f77d1e577d985cc4"), "name" : "aaa", "age" : 21, "class" : 1 }
{ "_id" : ObjectId("6239db19f77d1e577d985cc5"), "name" : "bbb", "age" : 20, "class" : 2 }
{ "_id" : ObjectId("6239db19f77d1e577d985cc6"), "name" : "ccc", "age" : 21, "class" : 1 }
{ "_id" : ObjectId("6239db19f77d1e577d985cc7"), "name" : "ddd", "age" : 21, "class" : 2 }

修改满足范围的数据

把年龄大于20的人放入0班

> db.student.update({"age":{"$gt":20}},{"$set":{"class":0}},{multi:true})
WriteResult({ "nMatched" : 3, "nUpserted" : 0, "nModified" : 3 })
> db.student.find()
{ "_id" : ObjectId("6239db19f77d1e577d985cc3"), "name" : "000", "age" : 20, "class" : 1 }
{ "_id" : ObjectId("6239db19f77d1e577d985cc4"), "name" : "aaa", "age" : 21, "class" : 0 }
{ "_id" : ObjectId("6239db19f77d1e577d985cc5"), "name" : "bbb", "age" : 20, "class" : 2 }
{ "_id" : ObjectId("6239db19f77d1e577d985cc6"), "name" : "ccc", "age" : 21, "class" : 0 }
{ "_id" : ObjectId("6239db19f77d1e577d985cc7"), "name" : "ddd", "age" : 21, "class" : 0 }

使用multi:true来改变所有满足条件的数据

删除指定数据值

> db.student.update({"name":"000"},{"$unset":{"name":"000"}})
WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 })
> db.student.find()
{ "_id" : ObjectId("6239db19f77d1e577d985cc3"), "age" : 20, "class" : 1 }
{ "_id" : ObjectId("6239db19f77d1e577d985cc4"), "name" : "aaa", "age" : 21, "class" : 0 }
{ "_id" : ObjectId("6239db19f77d1e577d985cc5"), "name" : "bbb", "age" : 20, "class" : 2 }
{ "_id" : ObjectId("6239db19f77d1e577d985cc6"), "name" : "ccc", "age" : 21, "class" : 0 }
{ "_id" : ObjectId("6239db19f77d1e577d985cc7"), "name" : "ddd", "age" : 21, "class" : 0 }

修改索引名

把aaa的索引name改为newname

> db.student.update({"name":"aaa"},{"$rename":{"name":"newname"}})
WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 })
> db.student.find()
{ "_id" : ObjectId("6239db19f77d1e577d985cc3"), "age" : 20, "class" : 1 }
{ "_id" : ObjectId("6239db19f77d1e577d985cc4"), "age" : 21, "class" : 0, "newname" : "aaa" }
{ "_id" : ObjectId("6239db19f77d1e577d985cc5"), "name" : "bbb", "age" : 20, "class" : 2 }
{ "_id" : ObjectId("6239db19f77d1e577d985cc6"), "name" : "ccc", "age" : 21, "class" : 0 }
{ "_id" : ObjectId("6239db19f77d1e577d985cc7"), "name" : "ddd", "age" : 21, "class" : 0 }

对原数据进行增减操作

让bbb的age加2

> db.student.update({"name":"bbb"},{$inc:{"age":2}})
WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 })
> db.student.find()
{ "_id" : ObjectId("6239db19f77d1e577d985cc3"), "age" : 20, "class" : 1 }
{ "_id" : ObjectId("6239db19f77d1e577d985cc4"), "age" : 21, "class" : 0, "newname" : "aaa" }
{ "_id" : ObjectId("6239db19f77d1e577d985cc5"), "name" : "bbb", "age" : 22, "class" : 2 }
{ "_id" : ObjectId("6239db19f77d1e577d985cc6"), "name" : "ccc", "age" : 21, "class" : 0 }
{ "_id" : ObjectId("6239db19f77d1e577d985cc7"), "name" : "ddd", "age" : 21, "class" : 0 }

save()方法

save() 方法通过传入的文档来替换已有文档，_id 主键存在就更新，不存在就插入。

把zs修改回来

> db.student.save({"_id" : ObjectId("6239db19f77d1e577d985cc3"), "name" : "zs", "age" : 20, "class" : 1 })
WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 })
> db.student.find()
{ "_id" : ObjectId("6239db19f77d1e577d985cc3"), "name" : "zs", "age" : 20, "class" : 1 }
{ "_id" : ObjectId("6239db19f77d1e577d985cc4"), "age" : 21, "class" : 0, "newname" : "aaa" }
{ "_id" : ObjectId("6239db19f77d1e577d985cc5"), "name" : "bbb", "age" : 22, "class" : 2 }
{ "_id" : ObjectId("6239db19f77d1e577d985cc6"), "name" : "ccc", "age" : 21, "class" : 0 }
{ "_id" : ObjectId("6239db19f77d1e577d985cc7"), "name" : "ddd", "age" : 21, "class" : 0 }