Partager via

Interroger des documents dans Azure Cosmos DB for MongoDB à l’aide de .NET

  • Article

S’APPLIQUE À : MongoDB

Utilisez des requêtes pour trouver des documents dans une collection.

Notes

Les exemples d’extraits de code sont disponibles sur GitHub en tant que projet .NET.

Documentation de référence sur l’API pour MongoDB | Package MongoDB (NuGet)

Rechercher des documents

Pour rechercher des documents, utilisez un filtre de requête sur la collection pour définir la façon dont les documents sont recherchés.

// 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"]);
}

Voir aussi