How do I handle Database Connections with Dapper in .NET?

Question

I\'ve been playing with Dapper, but I\'m not sure of the best way to handle the database connection.

Most examples show the connection object being created in the

Answer 1

Best practice is a real loaded term. I like a DbDataContext style container like Dapper.Rainbow promotes. It allows you to couple the CommandTimeout, transaction and other helpers.

For example:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Data.SqlClient;

using Dapper;

// to have a play, install Dapper.Rainbow from nuget

namespace TestDapper
{
    class Program
    {
        // no decorations, base class, attributes, etc 
        class Product 
        {
            public int Id { get; set; }
            public string Name { get; set; }
            public string Description { get; set; }
            public DateTime? LastPurchase { get; set; }
        }

        // container with all the tables 
        class MyDatabase : Database
        {
            public Table Products { get; set; }
        }

        static void Main(string[] args)
        {
            var cnn = new SqlConnection("Data Source=.;Initial Catalog=tempdb;Integrated Security=True");
            cnn.Open();

            var db = MyDatabase.Init(cnn, commandTimeout: 2);

            try
            {
                db.Execute("waitfor delay '00:00:03'");
            }
            catch (Exception)
            {
                Console.WriteLine("yeah ... it timed out");
            }


            db.Execute("if object_id('Products') is not null drop table Products");
            db.Execute(@"create table Products (
                    Id int identity(1,1) primary key, 
                    Name varchar(20), 
                    Description varchar(max), 
                    LastPurchase datetime)");

            int? productId = db.Products.Insert(new {Name="Hello", Description="Nothing" });
            var product = db.Products.Get((int)productId);

            product.Description = "untracked change";

            // snapshotter tracks which fields change on the object 
            var s = Snapshotter.Start(product);
            product.LastPurchase = DateTime.UtcNow;
            product.Name += " World";

            // run: update Products set LastPurchase = @utcNow, Name = @name where Id = @id
            // note, this does not touch untracked columns 
            db.Products.Update(product.Id, s.Diff());

            // reload
            product = db.Products.Get(product.Id);


            Console.WriteLine("id: {0} name: {1} desc: {2} last {3}", product.Id, product.Name, product.Description, product.LastPurchase);
            // id: 1 name: Hello World desc: Nothing last 12/01/2012 5:49:34 AM

            Console.WriteLine("deleted: {0}", db.Products.Delete(product.Id));
            // deleted: True 


            Console.ReadKey();
        }
    }
}