.net原生态sql数据库修改

using System.Data.SqlClient;

string connectionString = "your_connection_string";
string query = "SELECT * FROM Users WHERE Username = @username AND Password = @password";

using (SqlConnection connection = new SqlConnection(connectionString))
{
    SqlCommand command = new SqlCommand(query, connection);
    command.Parameters.AddWithValue("@username", username);
    command.Parameters.AddWithValue("@password", password);

    connection.Open();
    SqlDataReader reader = command.ExecuteReader();
    // 处理结果
}

using (SqlConnection connection = new SqlConnection(connectionString))
{
    // 执行数据库操作
}

using (SqlConnection connection = new SqlConnection(connectionString))
{
    connection.Open();
    SqlTransaction transaction = connection.BeginTransaction();

    try
    {
        SqlCommand command1 = new SqlCommand("UPDATE Table1 SET Column1 = @value1 WHERE Id = @id1", connection, transaction);
        command1.Parameters.AddWithValue("@value1", value1);
        command1.Parameters.AddWithValue("@id1", id1);
        command1.ExecuteNonQuery();

        SqlCommand command2 = new SqlCommand("UPDATE Table2 SET Column2 = @value2 WHERE Id = @id2", connection, transaction);
        command2.Parameters.AddWithValue("@value2", value2);
        command2.Parameters.AddWithValue("@id2", id2);
        command2.ExecuteNonQuery();

        transaction.Commit();
    }
    catch (Exception ex)
    {
        transaction.Rollback();
        // 处理异常
    }
}