2个文档在MongoDB中合并 [英] 2 documents merge in MongoDB
本文介绍了2个文档在MongoDB中合并的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
我需要从MongoDB中的不同集合(其中有1个公共字段，对数据库没有更改)的两个文档中获取数据.我是新手，请帮助我
I need to get data from two documents from different collections(1 common field in them, no change to the db) in MongoDB. I am a newbie and please help me with this
a = db.users.find(username:'abc@xyz.com')
b = db.tasks.find(username:'abc@xyz.com')
我如何获得合并了a和b的变量c?
How to I get a variable c which has a and b merged?
请帮助.这可能微不足道，但对我有帮助.
Please help. This may be trivial but help me.
推荐答案
嘿，如果用户在两个集合中都是唯一的，请使用函数findOne()，因为find()返回一个游标.因此，要在mongoDB控制台中实现两个对象的合并，可以使用以下代码:
Hey if the user is unique in both collections use function findOne(), because find() returns a cursor. So to achieve a merge of two objects in the mongoDB console you can use the bellow code:
function mergeObjects(a,b) {
res = new Object();
for (attr in a)
res[attr] = a[attr];
for (attr in b)
res[attr] = b[attr];
// only if you wanna save it in a document again
delete res["_id"];
return res;
}
a = db.users.findOne({"username" : 'abc@xyz.com'})
b = db.tasks.findOne({"username" : 'abc@xyz.com'})
c = mergeObjects(a,b)
希望这可以解决您的问题.
Hopefully this solve your problems.
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