[英]How to join collections in mongodb
I have a collection where data is stored by a owner and owner id is also stored along with data. 我有一个集合,其中数据由所有者存储,所有者ID也与数据一起存储。 On other hand there is another collection in which owner details are stored.
另一方面,还有另一个集合,其中存储了所有者详细信息。
{
"_id" : ObjectId("58103aac9899ff238cbae413"),
"id" : 10585131,
"title" : "Edfwef EdfwefE dfwefE dfwefEd fwef",
"category" : "Furniture",
"condition" : "Brand New",
"brand" : "Samsung",
"price" : "3434",
"description" : "sdvsdfv",
"date" : ISODate("2016-10-26T05:10:04.240Z"),
"ownerId" : "40903aac9899er238cbae598",
"__v" : 0
}
Now I am fetching above data and showing on a HTML file . 现在,我正在获取上述数据并显示在HTML文件中。 On same html file where data are fetching, I want to show owner details on the basis of ownerId.
在要获取数据的同一HTML文件上,我想根据ownerId显示所有者详细信息。 I mean how to join two collections in mongodb?
我的意思是如何在mongodb中加入两个集合? Please help.
请帮忙。
Thanks. 谢谢。
Updated: 更新:
admodel 广告模型
`var adSchema=new Schema({ id:{type:Number}, title:{type:String, required:true}, category:{type:String}, condition:{type:String}, brand:{type:String}, price:{type:String}, city:{type:String}, town:{type:String}, description:{type:String}, image:{type:String}, date:{type:Date}, ownerId:{type:Schema.Types.ObjectId, ref: 'user'} }); module.exports=mongoose.model('ads', adSchema);`
user 用户
`var UserSchema=new Schema({ name:{type:String, require:true}, password:{type:String, require:true, unique:true,}, email:{type:String, require:true, unique:true,}, mobile:{type:String} }); module.exports = mongoose.model('User', UserSchema);`
Inserting Data 插入资料
`apiRoutes.post('/adcreate',upload ,function(req, res, next){
var token=req.headers.authorization;
var owner=jwt.decode(token, config.secret);
var currentDate=Date.now();
var adId=Math.floor(Math.random()*13030978)+1;
var ad=new admodel({
id:adId,
title: req.body.title,
category:req.body.category,
condition:req.body.condition,
brand:req.body.brand,
price:req.body.price,
city:req.body.city,
town:req.body.town,
description:req.body.description,
date:currentDate,
ownerId:owner.id
}) ;
ad.save(function(err, data){
if(err){
return res.json({success:false, msg:'Ad not Posted'});
}else{
res.json({succes:true, msg:'Successfully ad Posted'});
}
});
});`
Fetching Data 取得资料
`apiRoutes.get('/individualads/:id', function(req, res,next){ admodel.findOne({_id:req.params.id}).populate('ownerId').exec(function(err, data){ if(err){ res.json(err); } else{ console.log(data); res.json(data); } }); });`
You can try as below and replace the properties as per your db collection 您可以尝试如下操作,并根据您的数据库集合替换属性
Reference Link: https://docs.mongodb.com/v3.2/reference/operator/aggregation/lookup/ 参考链接: https : //docs.mongodb.com/v3.2/reference/operator/aggregation/lookup/
// I assume 'orders' is your first collection name
db.orders.aggregate([
{
$lookup:
{
from: "owners", // your second collection name
localField: "ownerId", // matched property in first collection
foreignField: "_id", // matched property to join to the second collection
as: "owner" // owner details output property
}
}
])
Using mongoose
as you requested, 根据您的要求使用
mongoose
,
On your admodel
, add ref
with the target (second) model name as below 在您
admodel
,加上ref
如下与目标(第二)型号名称
ownerId: {
type: Schema.Types.ObjectId,
ref: 'owner' // This should be a name of the second model name in which you want to join and fetch data
}
Then change the route
as below, 然后如下更改
route
,
apiRoutes.get('/individualads/:id', function(req, res,next){
admodel.findOne({_id:req.params.id}).populate('ownerId').exec(function(err, data){
if(err){
res.json(err);
} else{
console.log(data);
res.json(data);
}
});
});
可以这样:
db.owner.find({}).populate({'path':'ownerId','model':'owner'}).exec()
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