Sorting arrays in Mongo - arrays

Question

H have json document with array. As I can't add to beginning of array with push or addtoset I need to sort array. Example
{
"Component": [
{
"Id": "PDP-1",
"Links": {"Link": [
{
"Text": "Western Division",
"Url": "/1x7-en70ai/last-minute-holidays-western-division",
"Title": "Last minute holidays Western Division"
},
{
"Text": "Browse Regions ",
"Url": "/1x7-en6uly-10ts/last-minute-holidays-gambia/regions",
"Title": "Last minute holidays Gambia",
"Style": "BrowseForMore"
},
{
"Text": "City of Banjul",
"Url": "/1x6-en6vq7/holidays-city-of-banjul",
"Title": "City of Banjul Holidays"
},
{
"Text": "Western Division",
"Url": "/1x6-en70ai/holidays-western-division",
"Title": "Western Division Holidays"
}
]},
"Title": "Regions",
"Type": "PDP"
},
{
"Id": "PDP-2",
"Links": {"Link": [
{
"Text": "Bijilo",
"Url": "/1x7-enbmy6/last-minute-holidays-bijilo",
"Title": "Last minute holidays Bijilo"
},
{
"Text": "Browse Cities ",
"Url": "/1x7-en6uly-10tt/last-minute-holidays-gambia/cities",
"Title": "Last minute holidays Gambia",
"Style": "BrowseForMore"
},
{
"Text": "Banjul Beach",
"Url": "/1x6-enakgm/holidays-banjul-beach",
"Title": "Banjul Beach Holidays"
},
{
"Text": "Bijilo",
"Url": "/1x6-enbmy6/holidays-bijilo",
"Title": "Bijilo Holidays"
},
{
"Text": "Brufut Heights",
"Url": "/1x6-encok8/holidays-brufut-heights",
"Title": "Brufut Heights Holidays"
},
{
"Text": "Kololi",
"Url": "/1x6-enpnle/holidays-kololi",
"Title": "Kololi Holidays"
},
{
"Text": "Kotu",
"Url": "/1x6-enq067/holidays-kotu",
"Title": "Kotu Holidays"
}
]},
"Title": "Cities",
"Type": "PDP"
}
],
"Id": "118431",
"Template": {
"PageTemplate": {
"Code": "2B2",
"text": "041 - TEMP2 - COP_CONCOU_{LAST MINUTE}"
},
"Category": {
"Code": "1X7",
"Type": "Product",
"text": "Last minute holidays"
},
"GeoObject": {
"Code": "EN6ULY",
"text": "Gambia, The"
},
"GeoObjectType": {
"Code": "1A",
"text": "Political"
},
"GeoObjectSubType": {
"Code": "10TR",
"text": "Country"
}
},
"Type": "Content",
"Url": "/1x7-en6uly/last-minute-holidays-gambia",
"_id": {"$oid": "528492d4c90fa9fcd0436929"}
}
I want to sort this by Style in Links.Link 'BrowseForMore'. Any idea how to do it? I thought I could add dummy array with push which could then sort it the way I want. Any help appreciated

Answer 1

You appear to want to update the array and keep the sort order with your Links.Link.Style value at the front of the list. In which case use the $sort modifier with update.
db.collection.update(
{ _id: id },
{ $push: { "Links.Link: {$each: [doc], $sort { Style: -1 }}} }
)
The $each operator is required even if there is only one document, but can take many.
if you are trying to use $addToSet to maintain unique documents the official MongoDB line is that sets are considered to be unordered and hence the modifiers are not available here.