CODEWITHSUNDEEP
mongodbmongodb-querymongodb-java
phani sekhar
phani sekhar

Reputation: 107

How to get all the parents and children of a document in mongodb

I recently started working on mongodb. My simple application will have Geo hierarchy like

Continet-->Country-->Region--->Resort-->Accommodation

My data will be like this

 {
    "_id" : ObjectId("54854d5af2ef42fe7d4d2a44"),
    "name" : "Europe",
    "parent" : "",
    "type" : "Continent",
    "synonym" : "",
    "code" : "EEE"
}
{
    "_id" : ObjectId("54854d5af2ef42fe7d4d2a47"),
    "name" : "Bulgaria",
    "parent" : "EEE",
    "type" : "Country",
    "synonym" : "",
    "code" : "BGR"
}
{
    "_id" : ObjectId("54854d5af2ef42fe7d4d2a45"),
    "name" : "Albania",
    "parent" : "EEE",
    "type" : "Country",
    "synonym" : "",
    "code" : "ALB"
}
{
    "_id" : ObjectId("54854d5af2ef42fe7d4d2a48"),
    "name" : "Bourgas Region",
    "parent" : "BGR",
    "type" : "Region",
    "synonym" : "",
    "code" : "002682"
}
{
    "_id" : ObjectId("54854d5af2ef42fe7d4d2a49"),
    "name" : "Obzor",
    "parent" : "002682",
    "type" : "Resort",
    "synonym" : "",
    "code" : "002911"
}
{
    "_id" : ObjectId("54854d5af2ef42fe7d4d2a4a"),
    "name" : "Sunny Beach",
    "parent" : "002682",
    "type" : "Resort",
    "synonym" : "",
    "code" : "002548"
}
{
    "_id" : ObjectId("54854d5af2ef42fa7d4d2b3d"),
    "name" : "Hotel Park Avenue",
    "parent" : "002548",
    "type" : "Accommodation",
    "synonym" : "",
    "code" : "022548"
}

As shown above there will be only the direct parent available in every document.

Now I have to get all the parents and children to a document with "code" : "002548"

If I have the Resort code, i have to get all the Accommodations which have the respective resort as parent and i have to get the Destination, Country, Continent to which the resort belongs to.

I feel that there should be recursive queries to get this, I am using MongoTemplate for db operations.

Please Help me to get the best solution for this.

Thanks in advance.

Upvotes: 1

Views: 1967

Answers (2)

wdberkeley
wdberkeley

Reputation: 11671

It'd be helpful to know what kinds of queries you're running on these documents, but I'm guessing the levels of interest are Resort and Accomodation. You've structured the higher three levels as separate documents, but it seems to me they are properties of Resorts and Accomodations: a Resort is in a given region, country, continent. Moreover, regions, countries, and continents don't change very much. I think the higher-level geo information is a good candidate for being embedded in Resort and Accommodation documents:

{
    "_id" : ObjectId("54854d5af2ef42fa7d4d2b3d"),
    "name" : "Hotel Park Avenue",
    "type" : "Accommodation",
    "synonym" : "",
    "code" : "022548",
    "region" : "New York",
    "country" : "United States",
    "continent" : "North America"
}

With this kind of structure, finding the "parents" of an accommodation like the above is just looking at the region, country, continent field values. Finding the "children" of, e.g., a country is a simple query:

db.stuff.find({ "country" : "United States" })

Upvotes: 0

evanchooly
evanchooly

Reputation: 6233

mongodb doesn't support joins so you'll have to do multiple queries to walk up that hierarchy.

Upvotes: 3

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