Visual C++ .NET/Database ADO.net/OleDbCommand — различия между версиями
Admin (обсуждение | вклад) м (1 версия) |
Admin (обсуждение | вклад) м (1 версия) |
(нет различий)
|
Текущая версия на 12:06, 26 мая 2010
Using database Commands
#include "stdafx.h"
using namespace System;
using namespace System::Data;
using namespace System::Data::OleDb;
void main()
{
OleDbConnection^ myConnection = nullptr;
myConnection = gcnew OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;Data Source=Music.mdb");
myConnection->Open();
OleDbCommand^ myCommand = myConnection->CreateCommand();
myCommand->CommandText = "SELECT COUNT(*) FROM Music";
myCommand = gcnew OleDbCommand("SELECT COUNT(*) FROM Music",myConnection);
Object^ count = myCommand->ExecuteScalar();
Console::WriteLine("There are {0} songs in the Music table", count);
myCommand->CommandText ="DELETE FROM Music WHERE Genre="N"";
int RecordsAffected = myCommand->ExecuteNonQuery();
Console::WriteLine("{0} songs were deleted from the Music table",RecordsAffected);
myConnection->Close();
}
Using database Parameter
#include "stdafx.h"
using namespace System;
using namespace System::Data;
using namespace System::Data::OleDb;
void main()
{
OleDbConnection^ myConnection = nullptr;
myConnection = gcnew OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;Data Source=Music.mdb");
myConnection->Open();
OleDbCommand^ MyCommand = gcnew OleDbCommand("SELECT COUNT(*) FROM Music WHERE Genre=@Genre",myConnection);
OleDbParameter^ parameter = gcnew OleDbParameter("@Genre",OleDbType::Char);
parameter->Direction = ParameterDirection::Input;
parameter->Value = "Techno/Classical";
MyCommand->Parameters->Add(parameter);
Object^ Count = MyCommand->ExecuteScalar();
Console::WriteLine("Count = {0}", Count);
myConnection->Close();
}