Ubuntu 22.04
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SQL Server 2022 : C# から利用する2023/11/24

 
C# からの SQL Server 利用例です。
[1] Microsoft .NET インストール済みを前提として例示します。
ubuntu@dlp:~$
dotnet --version

7.0.114
ubuntu@dlp:~$
dotnet new console -o MssqlTest

The template "Console App" was created successfully.

Processing post-creation actions...
Restoring /home/ubuntu/MssqlTest/MssqlTest.csproj:
  Determining projects to restore...
  Restored /home/ubuntu/MssqlTest/MssqlTest.csproj (in 74 ms).
Restore succeeded.

ubuntu@dlp:~$
cd MssqlTest

ubuntu@dlp:~/MssqlTest$
vi MssqlTest.csproj
<Project Sdk="Microsoft.NET.Sdk">

  <PropertyGroup>
    <OutputType>Exe</OutputType>
    <TargetFramework>net6.0</TargetFramework>
    <ImplicitUsings>enable</ImplicitUsings>
    <Nullable>enable</Nullable>
  </PropertyGroup>
  # 追記
  <ItemGroup>
    <PackageReference Include="System.Data.SqlClient" Version="4.4.0" />
  </ItemGroup>
</Project>
[2] 基本的な利用例です。データベースや接続ユーザーは事前に適当に作成したものを使用します。
# 事前準備のテスト用データベース

ubuntu@dlp:~$
sqlcmd -S localhost -U ubuntu -d SampleDB3 -Q 'select * from dbo.SampleTable;'

Password:
ID          First_Name         Last_Name
----------- ------------------ -------------------
          1 Ubuntu             Linux
          3 RedHat             RHEL 9 Plow
          5 Debian             Linux

(3 rows affected)

ubuntu@dlp:~$
cd MssqlTest

ubuntu@dlp:~/MssqlTest$
vi Program.cs
using System;
using System.Text;
using System.Data.SqlClient;

namespace SqlServerSample
{
    class Program
    {
        static void Main(string[] args)
        {
            try
            {
                SqlConnectionStringBuilder builder = new SqlConnectionStringBuilder();
                builder.DataSource = "127.0.0.1";
                builder.UserID = "ubuntu";
                builder.Password = "P@ssw0rd01";
                builder.InitialCatalog = "SampleDB3";

                Console.Write("Connecting to SQL Server... ");
                using (SqlConnection connection = new SqlConnection(builder.ConnectionString))
                {
                    connection.Open();
                    Console.WriteLine("Done.");
                    StringBuilder sb = new StringBuilder();

                    // SampleTable を Select
                    Console.WriteLine("Reading data from SampleTable...");
                    String sql = "select * from SampleTable;";
                    using (SqlCommand command = new SqlCommand(sql, connection))
                    {
                        using (SqlDataReader reader = command.ExecuteReader())
                        {
                            while (reader.Read())
                            {
                                Console.WriteLine(
                                    "{0} {1} {2}", 
                                    reader.GetInt32(0),
                                    reader.GetString(1),
                                    reader.GetString(2)
                                    );
                            }
                        }
                    }
                    
                    // SampleTable に Insert
                    Console.Write("\r\nInserting into SampleTable...\r\n");
                    sb.Clear();
                    sb.Append("insert SampleTable (First_Name, Last_Name) ");
                    sb.Append("values (@first_name, @last_name);");
                    sql = sb.ToString();
                    using (SqlCommand command = new SqlCommand(sql, connection))
                    {
                        command.Parameters.AddWithValue("@first_name", "Windows");
                        command.Parameters.AddWithValue("@last_name", "Microsoft");
                        int rowsAffected = command.ExecuteNonQuery();
                        Console.WriteLine(rowsAffected + " row(s) inserted");
                    }

                    // 特定の行を Update
                    String userToUpdate = "Ubuntu";
                    Console.Write("\r\nUpdating 'Last_Name' for user " + userToUpdate + "\r\n");
                    sb.Clear();
                    sb.Append("update SampleTable set Last_Name = N'Focal' where First_Name = @first_name");
                    sql = sb.ToString();
                    using (SqlCommand command = new SqlCommand(sql, connection))
                    {
                        command.Parameters.AddWithValue("@first_name", userToUpdate);
                        int rowsAffected = command.ExecuteNonQuery();
                        Console.WriteLine(rowsAffected + " row(s) updated\r\n");
                    }
                    
                    sql = "select * from SampleTable;";
                    using (SqlCommand command = new SqlCommand(sql, connection))
                    {
                        using (SqlDataReader reader = command.ExecuteReader())
                        {
                            while (reader.Read())
                            {
                                Console.WriteLine(
                                    "{0} {1} {2}",
                                    reader.GetInt32(0),
                                    reader.GetString(1),
                                    reader.GetString(2)
                                    );
                            }
                        }
                    }
                    
                    // 特定の行を Delete
                    String userToDelete = "Debian";
                    Console.Write("\r\nDeleting user '" + userToDelete + "'\r\n");
                    sb.Clear();
                    sb.Append("delete from SampleTable where First_Name = @first_name;");
                    sql = sb.ToString();
                    using (SqlCommand command = new SqlCommand(sql, connection))
                    {
                        command.Parameters.AddWithValue("@first_name", userToDelete);
                        int rowsAffected = command.ExecuteNonQuery();
                        Console.WriteLine(rowsAffected + " row(s) deleted");
                    }
                }
            }
            catch (SqlException e)
            {
                Console.WriteLine(e.ToString());
            }
        }
    }
}

ubuntu@dlp:~/MssqlTest$
dotnet restore

  Determining projects to restore...
  Restored /home/ubuntu/MssqlTest/MssqlTest.csproj (in 4.58 sec).
ubuntu@dlp:~/MssqlTest$
dotnet run

Connecting to SQL Server... Done.
Reading data from SampleTable...
1 Ubuntu Linux
3 RedHat RHEL 9 Plow
5 Debian Linux

Inserting into SampleTable...
1 row(s) inserted

Updating 'Last_Name' for user Ubuntu
1 row(s) updated

1 Ubuntu Focal
3 RedHat RHEL 9 Plow
5 Debian Linux
6 Windows Microsoft

Deleting user 'Debian'
1 row(s) deleted

ubuntu@dlp:~/MssqlTest$
sqlcmd -S localhost -U ubuntu -d SampleDB3 -Q 'select * from dbo.SampleTable;'

Password:
ID          First_Name          Last_Name
----------- ------------------- ------------------------
          1 Ubuntu              Focal
          3 RedHat              RHEL 9 Plow
          6 Windows             Microsoft

(3 rows affected)
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