VC+Ado动态创建Access数据库

ado技术目前已经成为连接数据库的主流技术，下面我来介绍如何使用ado来动态创建access数据库。

为了使用ado，必须引入微软的两个动态连接库msadox.dll和msado15.dll：

#pragma warning (disable: 4146)
#import "c:\Program Files\Common Files\system\ado\msadox.dll"
#import "c:\Program Files\Common Files\system\ado\msado15.dll" no_namespace rename("EOF", "EndOfFile")
#pragma warning (default: 4146)

将上述代码加入到stdafx.h文件中，由于ado是com组件，因此使用ado之前还要初始化com环境：

CoInitialize(NULL);

下面是一个在access数据库中创建表的sql语句的例子：

create table test
(
?name???text(20) WITH COMPRESSION not null,

?score???decimal(12,4) not null default 0,

?ID????? smallint not null default 0,

?birthday? date,

?sex????? char(1),

?CONSTRAINT CK_CH_SEX Check(SEX in ('N','V')),

?CONSTRAINT PK_ID Primary Key (ID)

);

使用ADOX::CatalogPtr来创建mdb文件：

HRESULT hr = S_OK;

//Set ActiveConnection of Catalog to this string
CString strcnn(_T("Provider=Microsoft.JET.OLEDB.4.0;Data source = d:\\test.mdb"));

try
{
???ADOX::_CatalogPtr m_pCatalog = NULL;
???hr = m_pCatalog.CreateInstance(__uuidof (ADOX::Catalog));

???if(FAILED(hr))

?? {

??????_com_issue_error(hr);

??? }

??? else

??? {
???????m_pCatalog->Create(_bstr_t(strcnn)); //Create MDB

??? }
}?
catch(_com_error &e)
{
?? // Notify the user of errors if any.
?? AfxMessageBox(_T(“error“));
}

创建一个连接对象打开刚刚建立的mdb文件：

_ConnectionPtr g_pConn;

g_pConn.CreateInstance(__uuidof(Connection));

g_pConn->Open("Provider=Microsoft.Jet.OLEDB.4.0;Data Source=d:\\test.mdb;",
?"", "", adConnectUnspecified);

下面函数用来执行sql文件中的sql语句：

// Function name : RunSqlScript
// Description?: 执行SQL脚本, peckermen@163.com, 2003-09-15
// Return type?: BOOL 成功返回TRUE
// Argument? : LPCSTR SqlScriptFile SQL脚本文件名
// Argument? : char separator SQL 分割符号, 缺省';'
// Argument? : char Remark??SQL 注释符号, 缺省'-'
BOOL RunSqlScript(LPCSTR SqlScriptFile, char separator = ';', char Remark = '-')
{
BOOL bRet = FALSE;
CFileFind finder;
CString ErrLong;
if (finder.FindFile(SqlScriptFile) == TRUE)
{
?CFile fSql;
?TCHAR *buffer, *pSQL, *p;
?
?fSql.Open(SqlScriptFile,Cfile&::modeRead);
?UINT nFileLength = fSql.GetLength();
?
?buffer = (TCHAR *)malloc((nFileLength + 1) * sizeof(TCHAR));
?_tcsnset(buffer, TCHAR('\0'), nFileLength + 1);

?UINT nBytesRead = fSql.Read(buffer,nFileLength); //把sql文件内容读入内存缓冲区
?fSql.Close();

?p = pSQL = buffer;
?BOOL bRunOK = FALSE;
?BOOL bInNote = FALSE;
?BOOL bSkip = FALSE;
?CString strSQL;
?TCHAR ch;
?ErrLog = _T("");
?while (p < (buffer + nFileLength)){
?????//判断是否是注释行
? if (bInNote)
? {
??if (*p == TCHAR('\x0a'))
?? bInNote = FALSE;
? }
? else
? {
??if ((*p == Remark) && (*(p+1) == Remark))
??{
?? bInNote = TRUE;
?? p++;
??}
??else
??{
??????//判断是否是sql语句结束标志
?? if (*p == separator){
???strSQL = _T("");
???bSkip = FALSE;
???while (pSQL < p)
???{
??? if (bSkip == FALSE){
????if ((*(pSQL) == Remark) &&(*(pSQL+1) == Remark))
????{
???? bSkip = TRUE;
???? pSQL++;
????}
????else
????{
???? ch = *pSQL;
???? strSQL = strSQL+ch;
????}
??? }
??? else{
????if (*pSQL = TCHAR('\x0a')){
???? bSkip = FALSE;
???? ch = TCHAR(' ');
???? strSQL = strSQL + ch;
????}
??? }
???
??? pSQL++;
???}
???pSQL = p + 1;
???ErrLog = ErrLog + _T("-- SQL Running ...\n");
???ErrLog = ErrLog + strSQL;
???
???_variant_t vRecords;

???m_nRecordsAffected = 0;

???try
???{
??? g_pConn->CursorLocation = adUseClient;
??? g_pConn->Execute(_bstr_t((LPCTSTR)strSQL), &vRecords, adExecuteNoRecords);
??? m_nRecordsAffected = vRecords.iVal;
??? bRunOK = TRUE;
???}
???catch(_com_error &e)
???{
??? bRunOK = FALSE;
???}
???
???if (bRunOK)
??? ErrLog = ErrLog + _T("\n-- Successed!\n");
???else
???{
??? ErrLog = ErrLog + _T("\n-- Failed!\n");
??? break;
???}
???
?? }
??}
? }
? p++;
?}
?free(buffer);
?bRet = bRunOK;
}
return bRet;
}

调用RunSqlScript创建access数据库中的表：

RunSqlScript(_T("d:\\test.sql"));

关闭数据库连接：

g_pConn->Close();

::CoUninitialize();

以上代码演示了怎样在vc中利用ado根据sql文件动态创建一个access数据库，欢迎指正。