mongodb Embedded document search on parent and child field - mongodb

Question

I have a nested embedded document CompanyProduct below is structure
{
"_id" : ObjectId("53d213c5ddbb1912343a8ca3"),
"CompanyID" : 90449,
"Name" : Company1,
"CompanyDepartment" : [
{
"_id" : ObjectId("53d213c5ddbb1912343a8ca4")
"DepartmentID" : 287,
"DepartmentName" : "Stores",
"DepartmentInventory" : [
{
"_id" : ObjectId("53b7b92eecdd765430d763bd"),
"ProductID" : 1,
"ProductName" : "abc",
"Quantity" : 100
},
{
"_id" : ObjectId("53b7b92eecdd765430d763bd"),
"ProductID" : 2,
"ProductName" : "xyz",
"Quantity" : 1
}
],
}
],
}
There can be N no of companies and each company can have N number of departments and each department can have N number of products.
I want to do a search to find out a particular product quantity under a particular company
I tried below query but it does not work. It returns all the products for the specific company, the less than 20 condition doesn't work.
db.CompanyProduct.find({$and : [{"CompanyDepartment.DepartmentInventory.Quantity":{$lt :20}},{"CompanyID":90449}]})
How should the query be?

Answer 1

You are searching from companyProduct's sub documents. So it will return you companyProduct whole document, it is NoSQL database , some how we do not need to normalize the collection , but your case it has to be normalize , like if you want to EDIT/DELETE any sub document and if there are thousand or millions of sub document then what will you do ... You need to make other collection with the name on CompanyDepartment and companyProduct collection should be
productCompany
{
"_id" : ObjectId("53d213c5ddbb1912343a8ca3"),
"CompanyID" : 90449,
"Name" : Company1,
"CompanyDepartment" : ['53d213c5ddbb1912343a8ca4'],
}
and other collection companyDepartment
{
"_id" : ObjectId("53d213c5ddbb1912343a8ca4")
"DepartmentID" : 287,
"DepartmentName" : "Stores",
"DepartmentInventory" : [
{
"_id" : ObjectId("53b7b92eecdd765430d763bd"),
"ProductID" : 1,
"ProductName" : "abc",
"Quantity" : 100
},
{
"_id" : ObjectId("53b7b92eecdd765430d763bd"),
"ProductID" : 2,
"ProductName" : "xyz",
"Quantity" : 1
}
],
}
after this you got array of companyDeparment' ID and only push and pull query will be used on productCompany

Answer 2

A Solution can be
db.YourCollection.aggregate([
{
$project:{
"CompanyDepartment.DepartmentInventory":1,
"CompanyID" : 1
}
},{
$unwind: "$CompanyDepartment"
},{
$unwind: "$CompanyDepartment.DepartmentInventory"
},{
$match:{$and : [{"CompanyDepartment.DepartmentInventory.Quantity":{$lt :20}},{"CompanyID":90449}]}
}
])
the result is
{
"result" : [
{
"_id" : ObjectId("53d213c5ddbb1912343a8ca3"),
"CompanyID" : 90449,
"CompanyDepartment" : {
"DepartmentInventory" : {
"_id" : ObjectId("53b7b92eecdd765430d763bd"),
"ProductID" : 2,
"ProductName" : "xyz",
"Quantity" : 1
}
}
}
],
"ok" : 1
}