MongoDb时间戳 [英] MongoDb timestamp

问题描述

我已经创建并想要导入一个虚拟集合。每个项目中的一个字段是创建和更新字段。我可以在source / json文件中添加什么内容，以便MongoDb将使用当前的日期和时间作为导入的值？

i have created and want to now import a dummy collection. one of the fields in each item are "created" and "updated" fields. what can i put in the source/json file so that MongoDb will use the current date and time as the value on import?

这个不工作

"created" : Date()

推荐答案

mongoimport 用于以CSV，TSV或JSON格式导入现有的数据。如果要插入新字段（例如创建的 timestamp），则必须为它们设置一个值。

mongoimport is intended for importing data existing data in CSV, TSV, or JSON format. If you want to insert new fields (such as a created timestamp) you will have to set a value for them.

例如，如果要将创建的时间戳设置为当前时间，可以从命令行获取一个unix时间戳（从时间开始是秒） ：

For example, if you want to set the created timestamp to the current time, you could get a unix timestamp from the command line (which will be seconds since the epoch):

$ date +%s
1349960286

$ < date> 表示 mongoimport expects是一个64位有符号整数，表示毫秒，时代。您需要将unixtime秒值乘以1000并将其包含在您的JSON文件中：

The JSON <date> representation that mongoimport expects is a 64-bit signed integer representing milliseconds since the epoch. You'll need to multiply the unixtime seconds value by 1000 and include in your JSON file:

{ "created": Date(1349960286000) }

另一种方法是将已创建的时间戳添加到文档插入后。

An alternative approach would be to add the created timestamps to documents after they have been inserted.

例如：

db.mycoll.update(
    {created: { $exists : false }},    // Query criteria
    { $set : { created: new Date() }}, // Add 'created' timestamp
    false, // upsert
    true   // update all matching documents
)   

这篇关于MongoDb时间戳的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！