Retrieve Partial Array Properties - json

Question

We are storing documents like this:
{
"FullName": "Jim",
"Children": [
{
"Name": "Sue",
"Hobbies": [
{
"Title": "Stamps",
"EnthusiasmLevel": 1
},
{
"Title": "Baseball",
"EnthusiasmLevel": 5
}
]
},
{
"Name": "Frank",
"Hobbies": [
{
"Title": "Dance",
"EnthusiasmLevel": 3
},
{
"Title": "Juggling",
"EnthusiasmLevel": 2
}
]
}
]
}
Usually when we are retrieving this "Jim" record, we'd want the full details on him and his children, but in certain circumstances we are going to want his name and just each child's name and the title of each of their hobbies.
Is there a straight-forward (or not) way of going about retrieving just parts of these documents while retaining (or rebuilding on the fly) their structure?
If I try something like:
SELECT p.FullName, [{"Name": child.Name}] AS Children
FROM People AS p
JOIN child in p.Children
I can construct an array, but I (obviously, per the join) get a record per child instead of one. If I instead remove the join and try to access these properties via the parent collection, I can't get at them.
What I want to get back is:
{
"FullName": "Jim",
"Children": [
{
"Name": "Sue",
"Hobbies": [
{"Title": "Stamps"},
{"Title": "Baseball"}
]
},
{
"Name": "Frank",
"Hobbies": [
{"Title": "Dance"},
{"Title": "Juggling"}
]
}
]
}
Even if I had to lose the structure, I'd still want to get back a single record representing "Jim" that contains his children's names and hobbies, but right now I'm just retrieving everything and doing the filtering on the client side, which is less than ideal.
Is what I'm after possible?

Answer 1

Based on your situation, I suggest you using Stored Procedure to process your data on the server side. I test sample code for you and it matches your requirements.
Sample Code:
function sample() {
var collection = getContext().getCollection();
var isAccepted = collection.queryDocuments(
collection.getSelfLink(),
'SELECT p.FullName, p.Children FROM People AS p',
function (err, feed, options) {
if (err) throw err;
if (!feed || !feed.length) {
var response = getContext().getResponse();
response.setBody('no docs found');
}
else {
var response = getContext().getResponse();
var returnResult = [];
for(var i = 0;i<feed.length;i++){
var peopleObj = feed[i];
ChildrenArray = [];
for(var j = 0;j<peopleObj.Children.length;j++){
console.log(j)
var childObj = peopleObj.Children[j];
HobbiesArray = [];
for(var k = 0; k < childObj.Hobbies.length;k++){
var hobbyObj = childObj.Hobbies[k];
map ={};
map["Title"] = hobbyObj.Title;
HobbiesArray.push(map);
}
childObj.Hobbies = HobbiesArray;
}
ChildrenArray.push(childObj);
}
returnResult.push(peopleObj);
getContext().getResponse().setBody(returnResult);
}
});
if (!isAccepted) throw new Error('The query was not accepted by the server.');
}
Output :
[
{
"FullName": "Jim",
"Children": [
{
"Name": "Sue",
"Hobbies": [
{
"Title": "Stamps"
},
{
"Title": "Baseball"
}
]
},
{
"Name": "Frank",
"Hobbies": [
{
"Title": "Dance"
},
{
"Title": "Juggling"
}
]
}
]
}
]
Any concern , please feel free to let me know.

Answer 2

I would suggest a simpler query-only solution. A la:
select jim.FullName,
ARRAY(
select child.Name,
ARRAY(
select hobby.Title from hobby in child.Hobbies
) as "Hobbies"
from jim join child in jim.Children
) as "Children"
from jim
While SP does have its uses, in this case I would consider this solution preferred over the SP because:
it is a lot simpler
it is more maintainable as it would keep your query logic in single place, query could be ran on any DB, without requiring any special permissions or preparation on server
It is better to keep application logic out of data layer. I.e. having the logic in app makes it possible to concurrently use multiple versions of this query.
haven't tested, but I'm pretty sure it is cheaper by RU.