MongoDB(update字段更新)

$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
}