Abfragen von Dokumenten in Azure Cosmos DB for MongoDB mithilfe von .NET
GILT FÜR: MongoDB
Verwenden Sie Abfragen, um Dokumente in einer Sammlung zu finden.
Hinweis
Die Beispielcodeausschnitte sind auf GitHub als .NET-Projekt verfügbar.
API for MongoDB-Referenzdokumentation | MongoDB-Paket (NuGet)
Abfragen von Dokumenten
Verwenden Sie zum Suchen von Dokumenten einen Abfragefilter für die Sammlung, um die betreffenden Dokumente zu finden.
// insert documents to query
var products = new List<BsonDocument>()
{
new BsonDocument
{
{ "_id", new ObjectId("62b1f43a9446918500c875c5") },
{ "name", "Sand Surfboard" },
{ "category", "gear-surfboards" },
{ "count", 1 }
},
new BsonDocument
{
{ "_id", new ObjectId("12b1f43a9446918500c875c5") },
{ "name", "Ocean Surfboard" },
{ "category", "gear-surfboards" },
{ "count", 5 }
},
new BsonDocument
{
{ "_id", new ObjectId("55b1f43a9446918500c875c5") },
{ "name", "Beach Towel" },
{ "category", "gear-accessories" },
{ "count", 4 }
},
new BsonDocument
{
{ "_id", new ObjectId("33b1f43a9446918500c875c5") },
{ "name", "Sunglasses" },
{ "category", "gear-accessories" },
{ "count", 5 }
}
};
collection.InsertMany(products);
// Find by ID
var filter = Builders<BsonDocument>.Filter.Gt("_id", "62b1f43a9446918500c875c5");
var query1 = collection.Find<BsonDocument>(filter).FirstOrDefault();
Console.WriteLine($"Query by id: {query1["_id"]} \n");
// Find by doc property
var filter2 = Builders<BsonDocument>.Filter.Eq("name", "Sand Surfboard");
var query2 = collection.Find<BsonDocument>(filter2).FirstOrDefault();
Console.WriteLine($"Query by property: {query2["name"]} \n");
// Find all by property
var filter3 = Builders<BsonDocument>.Filter.Eq("category", "gear-surfboards");
var query3 = collection.Find<BsonDocument>(filter3);
Console.WriteLine("Query all by property:");
foreach (var item in query3.ToList())
{
Console.WriteLine(item["name"]);
}
// Find all in a collection
var query4 = collection.Find<BsonDocument>(new BsonDocument()).ToList();
Console.WriteLine("\nQuery all in a collection:");
foreach (var item in query4.ToList())
{
Console.WriteLine(item["name"]);
}
// Pagination - fine next 5 docs
// sort by name requires an index on name
var index = Builders<BsonDocument>.IndexKeys.Ascending("name");
collection.Indexes.CreateOne(new CreateIndexModel<BsonDocument>(index));
var sort = Builders<BsonDocument>.Sort.Ascending("name");
var query5 = collection.Find<BsonDocument>(new BsonDocument()).Sort(sort).Skip(2).Limit(2).ToList();
Console.WriteLine("\nQuery using pagination:");
foreach (var item in query5.ToList())
{
Console.WriteLine(item["name"]);
}