Transcript Advance topic : Write your program with ADO

Advance topic :
Write your program with ADO
Jing Min Quan(井民全)
National Chiao Tung University
Introduction
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ADO = ActiveX Data Objects
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Access and manipulate data from a database server
Benefits:
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ease of use
high speed
low memory
key features
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building client/server
Web-based applications.
Prerequisites
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Tool->Options->Directories->
1. [Show Directories for]: Library files
2. [Directories]: C:\program files\common files\system\ado
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Setup the Data Source
[系統管理工具]->資料來源 (ODBC)
[系統資料來源名稱]-> 新增; Access mdb
[選取資料庫]->指定檔案路徑
How to program–
Read the Data from Database
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1. Import the ADO library
#import <msado15.dll> rename( "EOF", "adoEOF" )
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2. Initial OLE
struct InitOle {
InitOle() { ::CoInitialize(NULL); }
~InitOle() { ::CoUninitialize(); }
} _init_InitOle_;
How to program–
Read the Data from Database
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Connect to the Database
ADODB::_ConnectionPtr Conn1 = NULL;
CREATEINSTANCE(Conn1,ADODB::Connection)
設定系統資料庫名稱,
username,passwd
_bstr_t bstrAccessConnect
( L"DSN=AdoDemo;UID=;PWD=;" );
Conn1->ConnectionString = bstrAccessConnect;
Conn1->Open( bstrEmpty, bstrEmpty, bstrEmpty, -1 );
開啟一個
synchronously 連線
How to program–
Read the Data from Database
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Create a Record Object
ADODB::_RecordsetPtr rs("ADODB.Recordset");
rs->Open("Authors",
//開啟Authors資料表
_variant_t((IDispatch *) Conn1, true), // ADO is a IDispatch interface
ADODB::adOpenStatic,
// 指定records為原資料的static copy.
ADODB::adLockReadOnly,
// 無法更改record 資料
ADODB::adCmdTable);
// 指定Authors是資料表
How to program–
Read the Data from Database
rs->MoveFirst();
while ( rs->adoEOF == VARIANT_FALSE )
{
long int xx= rs->Fields->GetItem( _variant_t( 0L ) )->Value;
_bstr_t KK=rs->Fields->Item[1L]->Value;
char *cString=(char*) KK;
取得Au_ID欄位
取得Name欄位
rs->MoveNext();
}
Move to next record
How to program–
Read the Data from Database
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Close the Connection
rs->Close();
Conn1->Close();
Ex:RecordSet.cpp
How to program–
Append the Data into Database
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Create a Recordset which can be updated.
ADODB::_RecordsetPtr rs("ADODB.Recordset");
rs->Open("Authors",
_variant_t((IDispatch *) Conn1, true),
ADODB::adOpenStatic,
ADODB::adLockReadOnly, // 無法更改record 資料
ADODB::adCmdTable);
ADODB::_RecordsetPtr rs("ADODB.Recordset");
rs->Open("Authors",
//開啟Authors資料表
_variant_t((IDispatch *) Conn1, true), // ADO is a IDispatch interface
ADODB::adOpenStatic,
// 指定records為原資料的static copy.
ADODB::adLockOptimistic,
ADODB::adCmdTable);
// 指定Authors是資料表
How to program–
Append the Data into Database
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Insert the data
看看這個Recordset
是否支援AddNew
rs->MoveFirst();
if( rs->Supports(ADODB::adAddNew))
{
// 若rs 支援AddNew這個功能
rs->AddNew();
rs->Fields->Item["Au_ID"]->Value=(long)1234;
rs->Fields->Item[1L]->Value="自強基金會";
rs->Update();
}
rs->Close();
Conn1->Close();
把資料update到資料庫中
實際的寫入資料庫
Reference
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Get the Help
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http://www.microsoft.com/data/ado/
Download the MADC 2.6 SDK
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http://www.microsoft.com/data/download.htm