How to connect to SQL Server from .Net Core without using Entity Framework?

Question

How can we connect to SQL Server from .Net Core without using Entity Framework?

Answer 1

Here is a solution for an ASP.NET MVC Core 3.1 project tested in Visual Studio 2019 community edition.

Create a small database in SQL Express.

Then add a few lines to appsettings.json for the connection strings:

  "ConnectionStrings": {
    //PROD on some server
    "ProdConnection": "Server=somePRODServerofYours;Database=DB_xxxxx_itemsubdb;User Id=DB_xxxxx_user;Password=xxsomepwdxx;Integrated Security=false;MultipleActiveResultSets=true;encrypt=true",

    //DEV on localhost
    "DevConnection": "Server=someDEVServerofYours;Database=DB_xxxxx_itemsubdb;User Id=DB_xxxxx_user;Password=xxsomepwdxx;Integrated Security=false;MultipleActiveResultSets=true;"
  },

Then use code similar to the following in your controller ....

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Mvc;
using Microsoft.AspNetCore.Hosting;
using Microsoft.Extensions.Hosting;
using Microsoft.Extensions.Configuration;
using System.Data.SqlClient;
using System.Data;

namespace SomeNameSpace.Controllers
{
    //This Model class should be saved somewhere else in your project.
    //It is placed here for simplicity.
    public class XtraSimpleContent
    {
        public string UserName { get; set; }
        public string References { get; set; }
        public string CreatedTime { get; set; }
    }

    public class CodeNotesController : Controller
    {
        public IConfiguration Configuration { get; }
        public string connStr = String.Empty;

        public CodeNotesController(IConfiguration configuration, IWebHostEnvironment env)
        {
            Configuration = configuration;
            if (env.IsDevelopment())
            {
                connStr = Configuration.GetConnectionString("DevConnection");
            }
            else
            {
                connStr = Configuration.GetConnectionString("ProdConnection");
            }
        }

        [HttpGet]
        public async Task CodeActionMethodToConnectToSQLnetCore()
        {
            //add  using System.Data.SqlClient;
            //     using System.Data;
            //Along with the using statements, you need the system assembly reference.
            //To add assembly you can do the following.
            //   install nuget package. Right Click on Project > Manage Nuget Packages > 
            //   Search & install 'System.Data.SqlClient' and make sure it is compatible with the type of project (Core/Standard);

            List aListOfItems = new List();

            string commandText = @"SELECT * FROM [dbo].[ItemSubmissions] 
                                        WHERE SUBMITTEREMAIL = @SUBMITTEREMAIL 
                                        ORDER BY CreationDatetime DESC";

            using (var connection = new SqlConnection(connStr))
            {
                await connection.OpenAsync();   //vs  connection.Open();
                using (var tran = connection.BeginTransaction())
                {
                    using (var command = new SqlCommand(commandText, connection, tran))
                    {
                        try
                        {
                            command.Parameters.Add("@SUBMITTEREMAIL", SqlDbType.NVarChar);
                            command.Parameters["@SUBMITTEREMAIL"].Value = "me@someDomain.org";

                            SqlDataReader rdr = await command.ExecuteReaderAsync();  // vs also alternatives, command.ExecuteReader();  or await command.ExecuteNonQueryAsync();

                            while (rdr.Read())
                            {
                                var itemContent = new XtraSimpleContent();
                                itemContent.UserName = rdr["RCD_SUBMITTERNAME"].ToString();
                                itemContent.References = rdr["RCD_REFERENCES"].ToString();
                                itemContent.CreatedTime = rdr["CreationDatetime"].ToString();

                                aListOfItems.Add(itemContent);
                            }
                        await rdr.CloseAsync();
                        }
                        catch (Exception Ex)
                        {
                            await connection.CloseAsync()
                            string msg = Ex.Message.ToString();
                            tran.Rollback();
                            throw;
                        }
                    }
                }
            }

            string totalinfo = string.Empty;
            foreach (var itm in aListOfItems)
            {
                totalinfo = totalinfo + itm.UserName + itm.References + itm.CreatedTime;
            }
            return Content(totalinfo);

        }
    }
}

Test it with something like:

https://localhost:44302/CodeNotes/CodeActionMethodToConnectToSQLnetCore