$set
- 查找name为"xiao"的数据，并设置其age为11
db.users.update({name:'xiao'},{$set:{age:11}})
结果为
/* 1 */
{
"_id" : ObjectId("5a193de63400d1e7d4e12d74"),
"name" : "xiao",
"age" : 11.0,
"address":"Hangzhou",
"qq":123456
}
注意:如果这样写
db.users.update({name:'xiao'},{age:11})
结果为
/* 1 */
{
"_id" : ObjectId("5a193de63400d1e7d4e12d74"),
"age" : 11.0
}
即除了_id和age,其他字段都会被洗掉
$unset
- 查找name为"xiao"的数据，并抹去其age字段
db.users.update({name:'xiao'},{$unset:{age:true}})
结果为
/* 1 */
{
"_id" : ObjectId("5a193de63400d1e7d4e12d74"),
"age" : 11.0,
"address":"Hangzhou",
"qq":123456
}
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