小编Ric*_*lli的帖子

我正在为我正在研究的项目尝试一种新方法,我刚开始学习Access数据库.我使用VB.net,我的问题是:如何查看数据库表中是否存在记录.我以为我明白了,但事实并非如此.我正在创建一个登录名,我希望它在尝试比较您输入的内容与数据库中的内容之前检查他们输入的用户名是否存在.我看到很多关于如何做到这一点的问题......但是对于VB.net 和 MS Access没有

这是我的代码:

Imports System.Data.OleDb
Public Class LoginForm1
    Dim provider As String
    Dim dataFile As String
    Dim connString As String
    Public myConnection As OleDbConnection = New OleDbConnection
    Public dr As OleDbDataReader
    Dim Errors As String
    Public Sub AccessAccountDatabase()
        provider = "Provider=Microsoft.ACE.OLEDB.12.0;Data Source ="
        dataFile = "C:\Users\Richard\Documents\Visual Studio 2010\Projects\CybSol Journal Database\CybSol Journal Database\cgi-bin\Data.mdb"
        connString = provider & dataFile
        myConnection.ConnectionString = connString
        Errors = ""
        Try
            myConnection.Open()
            Dim str As String
            str = "SELECT * FROM Accounts WHERE …

我正在尝试将字符串输出到基本.txt文件.它只是部分起作用,我的意思是它只接受我输入的任何内容的第一个单词.我需要能够没有字符限制(用户可以输入他们想要的多少)

#include <fstream>
#include <iostream>
#include <cstdlib>

using namespace std;

int main()
{

    ifstream in_stream;
    ofstream out_stream;

    in_stream.open("advice.txt");
    if (in_stream.fail())
    {
     cout << "input file opening failed.\n";
     exit(1);                     
    }


    char next;

    in_stream.get(next);
    while (! in_stream.eof())
    {
     cout << next;
     in_stream.get(next);      
    }


    out_stream.open("advice.txt", ios::app); //Append data to file
    if (out_stream.fail())
    {
     cout << "output file opening failed.\n";
     exit(1);                     
    }


    //Output text into the file (Problem is in here)

    string mystring;

    cin >> mystring, "\n\n";
    out_stream << " - " << mystring …