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Updated Example C# code showing MongoDB Transactions using the MongoDB .NET Driver (2.7+)
using MongoDB.Bson;
using MongoDB.Bson.Serialization.Attributes;
using MongoDB.Driver;
using System;
using System.Threading.Tasks;
namespace MongoDBTransaction
{
public static class Program
{
public class Product
{
[BsonId]
public ObjectId Id { get; set; }
[BsonElement("SKU")]
public int SKU { get; set; }
[BsonElement("Description")]
public string Description { get; set; }
[BsonElement("Price")]
public Double Price { get; set; }
}
// replace with your connection string if it is different
const string MongoDBConnectionString = "mongodb://localhost";
public static async Task Main(string[] args)
{
if (!await UpdateProductsAsync()) { Environment.Exit(1); }
Console.WriteLine("Finished updating the product collection");
Console.ReadKey();
}
private static async Task<bool> UpdateProductsAsync()
{
// Create client connection to our MongoDB database
var client = new MongoClient(MongoDBConnectionString);
// Create the collection object that represents the "products" collection
var database = client.GetDatabase("MongoDBStore");
var products = database.GetCollection<Product>("products");
// Clean up the collection if there is data in there
await database.DropCollectionAsync("products");
// collections can't be created inside a transaction so create it first
await database.CreateCollectionAsync("products");
// Create a session object that is used when leveraging transactions
using (var session = await client.StartSessionAsync())
{
// Begin transaction
session.StartTransaction();
try
{
// Create some sample data
var tv = new Product { Description = "Television",
SKU = 4001,
Price = 2000 };
var book = new Product { Description = "A funny book",
SKU = 43221,
Price = 19.99 };
var dogBowl = new Product { Description = "Bowl for Fido",
SKU = 123,
Price = 40.00 };
// Insert the sample data
await products.InsertOneAsync(session, tv);
await products.InsertOneAsync(session, book);
await products.InsertOneAsync(session, dogBowl);
var resultsBeforeUpdates = await products
.Find<Product>(session, Builders<Product>.Filter.Empty)
.ToListAsync();
Console.WriteLine("Original Prices:\n");
foreach (Product d in resultsBeforeUpdates)
{
Console.WriteLine(
String.Format("Product Name: {0}\tPrice: {1:0.00}",
d.Description, d.Price)
);
}
// Increase all the prices by 10% for all products
var update = new UpdateDefinitionBuilder<Product>()
.Mul<Double>(r => r.Price, 1.1);
await products.UpdateManyAsync(session,
Builders<Product>.Filter.Empty,
update); //,options);
// Made it here without error? Let's commit the transaction
await session.CommitTransactionAsync();
}
catch (Exception e)
{
Console.WriteLine("Error writing to MongoDB: " + e.Message);
await session.AbortTransactionAsync();
return false;
}
// Let's print the new results to the console
Console.WriteLine("\n\nNew Prices (10% increase):\n");
var resultsAfterCommit = await products
.Find<Product>(session, Builders<Product>.Filter.Empty)
.ToListAsync();
foreach (Product d in resultsAfterCommit)
{
Console.WriteLine(
String.Format("Product Name: {0}\tPrice: {1:0.00}",
d.Description, d.Price)
);
}
return true;
}
}
}
}
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