在VS 2012 Express中，我需要使用数据库连接还是全部内置？

using System.Data.SqlServerCe;

private void Form1_Load(object sender, EventArgs e)
{
    string connectionString = @"Data Source=MyDatabase.sdf;Persist Security Info=False;";
    using (SqlCeConnection conn = new SqlCeConnection(connectionString))
    {
        conn.Open();
        string query = "SELECT * FROM YourTableName";
        using (SqlCeCommand cmd = new SqlCeCommand(query, conn))
        {
            using (SqlCeDataReader reader = cmd.ExecuteReader())
            {
                while (reader.Read())
                {
                    // 处理数据
                }
            }
        }
    }
}

using MySql.Data.MySqlClient;

private void Form1_Load(object sender, EventArgs e)
{
    string connectionString = "server=localhost;user=root;password=yourpassword;database=yourdatabase";
    using (MySqlConnection conn = new MySqlConnection(connectionString))
    {
        conn.Open();
        string query = "SELECT * FROM YourTableName";
        using (MySqlCommand cmd = new MySqlCommand(query, conn))
        {
            using (MySqlDataReader reader = cmd.ExecuteReader())
            {
                while (reader.Read())
                {
                    // 处理数据
                }
            }
        }
    }
}