.Net 6: C# で MariaDB の Read

プロジェクトの作成

mkdir Read01
cd Read01
dotnet new console
dotnet add package MySql.Data --version 8.0.30

フォルダー構造

$ tree -L 1
.
├── Program.cs
├── Read01.csproj
└── obj

Program.cs

// ----------------------------------------------------------------
/*
	Program.cs

					Aug/09/2022

*/
// ----------------------------------------------------------------
using System;
using MySql.Data.MySqlClient;

// ----------------------------------------------------------------
public static class maria_read
{
public static void Main (string[] args)
{
	string server = "localhost";
	string str_db = "city";
	string user = "scott";
	string password = "tiger123";
	string str_connect = "Server=" + server + 
	";User Id=" + user + ";Password=" + password + ";Database=" + str_db + ";";

	MySqlConnection conn = new MySqlConnection (str_connect);

	Console.Error.WriteLine ("*** 開始 ***");

	conn.Open();

	MySqlCommand command = new MySqlCommand("select * from cities", conn);

	MySqlDataReader dr = command.ExecuteReader();


	while(dr.Read())
		{
		for (int it = 0; it < dr.FieldCount; it++)
			{
			Console.Write("{0} \t", dr[it]);
			}
		Console.WriteLine();
		}

	conn.Close();

	Console.Error.WriteLine ("*** 終了 ***");
}

// ----------------------------------------------------------------
}
// ----------------------------------------------------------------

実行結果

$ dotnet run
*** 開始 ***
t3321 	岡山 	497125 	2009-8-4 	
t3322 	倉敷 	219687 	2009-9-2 	
t3323 	津山 	871392 	2009-10-8 	
t3324 	玉野 	923187 	2009-5-9 	
t3325 	笠岡 	651978 	2009-1-5 	
t3326 	井原 	395647 	2009-5-22 	
t3327 	総社 	412786 	2009-7-17 	
t3328 	高梁 	174835 	2009-3-4 	
t3329 	新見 	781324 	2009-10-12 	
*** 終了 ***