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Consultar documentos no Azure Cosmos DB for MongoDB usando .NET

  • Artigo

APLICA-SE AO: MongoDB

Use as consultas para localizar documentos em uma coleção.

Observação

Os trechos de código de exemplo estão disponíveis no GitHub como um projeto .NET.

Documentação de referência da API for MongoDB | Pacote do MongoDB (NuGet)

Consulta de documentos

Para localizar documentos, use um filtro de consulta na coleção para definir como os documentos são encontrados.

// 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"]);
}

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