{
"objects": [
{
"id": 123,
"tracking_datas": [
{
"id": 1,
"polygons": [1,3]
},
{
"id": 2,
"polygons": [3]
},
{
"id": 3,
"polygons": [1,2]
}
]
}
]
}
我有一個如上所述的json檔案。并且在我的NetCore專案中有一個滿足這個json的模型。我想獲取包含我在 mongodb 幫助下確定的多邊形 ID 的物件。我怎樣才能用 c# mongo db 做到這一點？
例如，我有一個參考陣列 requiredPolygons: [1,2] 并且我想在 json 中物件的跟蹤資料中獲取包含這些多邊形 ID 的資料。預期結果如下。
{
"objects":
[
{
"id": 123,
"tracking_datas":[
{
"id": 1,
"polygons": [1,3]
},
{
"id": 3,
"polygons": [1,2]
}
]
}
]
}
uj5u.com熱心網友回復：
public class Test
{
public ObjectId Id { get; set; }
public IEnumerable<Object> objects { get; set; }
[BsonExtraElements]
public BsonDocument UnmappedFields { get; set; } // I'm not sure why it's required, something wrong with mapping configuration,
// but it's a separate question
}
public class Object
{
public int id { get; set; }
public IEnumerable<TrackingData> tracking_datas { get; set; }
}
public class TrackingData
{
public int id { get; set; }
public IEnumerable<int> polygons { get; set; }
[BsonExtraElements]
public BsonDocument UnmappedFields { get; set; } // I'm not sure why it's required, something wrong with mapping configuration,
// but it's a separate question
}
var json = @"{
""objects"": [
{
""id"": 123,
""tracking_datas"": [
{
""id"": 1,
""polygons"": [1,3]
},
{
""id"": 2,
""polygons"": [3]
},
{
""id"": 3,
""polygons"": [1,2]
}
]
}
]
}";
var client = new MongoClient();
var db = client.GetDatabase("so_test");
var coll = db.GetCollection<BsonDocument>("coll");
coll.InsertOne(BsonDocument.Parse(json));
var ids = new[] { 1, 2 };
var typedColl = db.GetCollection<Test>("coll");
var result = typedColl
.Aggregate()
.Project(p =>
new Test
{
Id = p.Id,
objects = p.objects.Select(o =>
new Object
{
id = o.id,
tracking_datas = o.tracking_datas.Where(t => t.polygons.Any(p=>ids.Contains(p)))
})
}
)
.ToList();
uj5u.com熱心網友回復：
干得好：
db.collection.find({
"objects.tracking_datas.polygons": {
$in: [
1,
2
]
}
})
https://mongoplayground.net/p/MDlIV3YPkZB
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