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//创建连接的方法

TADOConnection *Conn = new TADOConnection(NULL);
Conn->Provider = 数据库Provider的属性值;
Conn->ConnectionString = 连接字符串值;
Conn->LoginPrompt = false;
try
{
  Conn->Connected = true;
}
catch(Exception &e)
{
  //连接有错误, 错误信息为 e.Message
}


TADOQuery *Qy = new TADOQuery(NULL);
Qy->Connection = Conn; //就是前面创建的连接，或者用窗体里面的，例如 Qy->Connection = Form1->AdoConnection1;
Qy->SQL->Text = "select * from mytable";
try
{
  //读出字段值
  Qy->Active = true;
  AnsiString s = qy->FieldByName("字段名")->AsString; //读出字段的值

  //直接从查询结果里面修改字段值，并且储存到表里面
  Qy->Edit();
  Qy->FieldByName("字段名")->AsString = "字段值";
  Qy->Post();

  //下面用 update 语句修改表内容：
  Qy->Active = false;
  Qy->SQL->Text = "update mytable set 字段名='字段值' where 条件";
  Qy->ExecSQL();
}
catch(Exception &e)
{
  //执行有错误, 错误信息为 e.Message
}
delete Qy; //不用了的时候需要用 delete 释放占用的资源


delete Conn; //连接不用了的时候需要用 delete 释放占用的资源

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