如何将 MongoDB 中的属性从文本类型转换为日期类型？
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How do I convert a property in MongoDB from text to date type?
提问by Jeff Fritz
In MongoDB, I have a document with a field called "ClockInTime"that was imported from CSV as a string.
在 MongoDB 中，我有一个包含"ClockInTime"从 CSV 导入为字符串的字段的文档。
What does an appropriate db.ClockTime.update()statement look like to convert these text based values to a date datatype?
db.ClockTime.update()将这些基于文本的值转换为日期数据类型的适当语句是什么样的？
回答by kristina
This code should do it:
这段代码应该这样做：
> var cursor = db.ClockTime.find()
> while (cursor.hasNext()) {
... var doc = cursor.next();
... db.ClockTime.update({_id : doc._id}, {$set : {ClockInTime : new Date(doc.ClockInTime)}})
... }
回答by Ciges
I have exactly the same situation as Jeff Fritz.
我和杰夫弗里茨的情况完全一样。
In my case I have succeed with the following simpler solution:
就我而言，我使用以下更简单的解决方案取得了成功：
db.ClockTime.find().forEach(function(doc) {
doc.ClockInTime=new Date(doc.ClockInTime);
db.ClockTime.save(doc);
})
回答by Salil Panikkaveettil
This is a generic sample code in python using pymongo
这是在 python 中使用 pymongo 的通用示例代码
from pymongo import MongoClient
from datetime import datetime
def fixTime(host, port, database, collection, attr, date_format):
#host is where the mongodb is hosted eg: "localhost"
#port is the mongodb port eg: 27017
#database is the name of database eg : "test"
#collection is the name of collection eg : "test_collection"
#attr is the column name which needs to be modified
#date_format is the format of the string eg : "%Y-%m-%d %H:%M:%S.%f"
#http://docs.python.org/2/library/datetime.html#strftime-and-strptime-behavior
client = MongoClient(host, port)
db = client[database]
col = db[collection]
for obj in col.find():
if obj[attr]:
if type(obj[attr]) is not datetime:
time = datetime.strptime(obj[attr],date_format)
col.update({'_id':obj['_id']},{'$set':{attr : time}})
for more info : http://salilpa.com/home/content/how-convert-property-mongodb-text-date-type-using-pymongo
更多信息：http: //salilpa.com/home/content/how-convert-property-mongodb-text-date-type-using-pymongo
回答by webDEVILopers
If you need to check if the field already has been converted you can use this condition:
如果您需要检查该字段是否已被转换，您可以使用以下条件：
/usr/bin/mongo mydb --eval 'db.mycollection.find().forEach(function(doc){
if (doc.date instanceof Date !== true) {
doc.date = new ISODate(doc.date);
db.mycollection.save(doc);
}
});'
Otherwise the command line may break.
否则命令行可能会中断。
回答by Xavier Guihot
Starting Mongo 4.x:
开始Mongo 4.x：
db.collection.update()can accept an aggregation pipeline, finally allowing the update of a field based on its current value (Mongo 4.2+).- There is a new
$toDateaggregation operator (Mongo 4.0).
db.collection.update()可以接受聚合管道，最终允许基于其当前值 (Mongo 4.2+)更新字段。- 有一个新的
$toDate聚合运算符 (Mongo 4.0)。
Such that:
这样：
// { a: "2018-03-03" }
db.collection.update(
{},
[{ $set: { a: { $toDate: "$a" } } }],
{ multi: true }
)
// { a: ISODate("2018-03-03T00:00:00Z") }
The first part
{}is the match query, filtering which documents to update (in this case all documents).The second part
[{ $set: { a: { $toDate: "$a" } } }]is the update aggregation pipeline (note the squared brackets signifying the use of an aggregation pipeline).$setis a new aggregation operator which in this case replaces the field's value. The replaced value being the field itself concerted to anISODateobject. Note howais modified directly based on its own value ($a).Don't forget
{ multi: true }, otherwise only the first matching document will be updated.
第一部分
{}是匹配查询，过滤要更新的文档（在本例中为所有文档）。第二部分
[{ $set: { a: { $toDate: "$a" } } }]是更新聚合管道（注意方括号表示使用聚合管道）。$set是一个新的聚合运算符，在这种情况下替换字段的值。被替换的值是与ISODate对象一致的字段本身。请注意如何a直接根据其自身的值 ($a) 进行修改。不要忘记
{ multi: true }，否则只会更新第一个匹配的文档。
