mysql连接方式

一、PHP使用MYSQL数据库方式

本例主要是用PHP连接MYSQL数据库。通过相关语句对SQL语句的执行，达到操作数据库的目的。

1、实例

$link_id=mysql_connect($hostname,$username,$password);
mysql_query("SET CHARACTER SET  utf8");
mysql_query("SET NAMES utf8");
$result=mysql_select_db("xyymg");
if( !$result )
{
    echo "连接数据库出错！";
    exit();
}
$search_sql_0 = "select webPicId, webPicTitle, webPicTime, webPicPath from web_pictable where webPicSort = $t_index";

    $res_search_0 = @mysql_query("$search_sql_0");
    $num_records = @mysql_num_rows( $res_search_0 );        //记录行总数

    $search_sql_1 = $search_sql_0." order by webPicId desc limit $init_record,$num_to_show";
    $res_search_1 = mysql_query("$search_sql_1");
    $t_picList = array();

    if( $res_search_1 )
    {
        while( $r = mysql_fetch_row( $res_search_1 ) )
        {
            $t_picSaveSmallPath = "./".PIC_SAVE_SMALL_PATH.$r[3];
            $t_picList[] = array( 'id'=>$r[0], 'title'=>$r[1], 'ttime'=>timeToDate( $r[2] ), 'smallPicPath'=>$t_picSaveSmallPath );
        }
    }

2、连接数据库

$con = mysql_connect("localhost","peter","abc123");
if (!$con)
  {
  die('Could not connect: ' . mysql_error());
  }
// some code
?>

3、断开数据库

$con = mysql_connect("localhost","peter","abc123");
if (!$con)
  {
  die('Could not connect: ' . mysql_error());
  }
// some code
mysql_close($con);
?>

4、用mysql_query() 执行SQL语句

5、从数据库表选取数据

$con = mysql_connect("localhost","peter","abc123");
if (!$con)
  {
  die('Could not connect: ' . mysql_error());
  }
mysql_select_db("my_db", $con);
$result = mysql_query("SELECT * FROM person");
while($row = mysql_fetch_array($result))
  {
  echo $row['FirstName'] . " " . $row['LastName'];
  echo "";
  }
mysql_close($con);
?>

 

6、ODBC实例

$conn=odbc_connect('northwind','','');
if (!$conn)
  {exit("Connection Failed: " . $conn);}
$sql="SELECT * FROM customers";
$rs=odbc_exec($conn,$sql);
if (!$rs)
  {exit("Error in SQL");}
echo "";    echo "";    echo "";    while (odbc_fetch_row($rs))    {      $compname=odbc_result($rs,"CompanyName");      $conname=odbc_result($rs,"ContactName");      echo "";      echo "";    }    odbc_close($conn);    echo "
    
    
    
    Companyname
    
    
    
    Contactname
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    $compname
    
    
    
    $conname
    
    
    
    
    
    
    
    
    
    
    
    ";
?>

二、VC连接数据库方式

本例使用VC连接Access数据库，连接方式为ADO

1、导入引用

#import "c:\program files\common files\system\ado\msado15.dll"\
no_namespace rename( "EOF", "adoEOF" )

2、初始化COM组建

CDbOpe::CDbOpe()
{
    CoInitialize(NULL);
}

3、连接数据库

//连数据库
BOOL CDbOpe::LinkDb(CString db, CString usr, CString psw)
{
    CString strDb;
    strDb.Format( _T("Provider=Microsoft.Jet.OLEDB.4.0;Data Source=%s"), db );
    m_pConnection.CreateInstance(__uuidof(Connection));

    try{
        m_pConnection->Open( (_bstr_t)strDb,(_bstr_t)usr,(_bstr_t)psw,adModeUnknown);
    }
    catch(_com_error e )
    {
        CString   errMessage;
        errMessage.Format( _T("连接数据库失败!\r\n错误信息:%s"),(char*)e.Description());
        AfxMessageBox( errMessage );
        return FALSE;
    }
    return TRUE;
}

4、执行SQL语句

BOOL CDbOpe::OpenTable( CString sql )
{
    m_pRecordset.CreateInstance(__uuidof(Recordset));
    // 在ADO操作中建议语句中要常用try...catch()来捕获错误信息，
    // 因为它有时会经常出现一些意想不到的错误。jingzhou xu
    try
    {
        m_pRecordset->Open( (_bstr_t)sql,// 查询DemoTable表中所有字段
        m_pConnection.GetInterfacePtr(),  // 获取库接库的IDispatch指针
        adOpenDynamic,
        adLockOptimistic,
        adCmdText);
    }
    catch(_com_error *e)
    {
        //AfxMessageBox(e->ErrorMessage());
        return FALSE;
    }
    return TRUE;
}

//执行SQL语句
BOOL CDbOpe::ExecutSql(CString sql)
{
    _variant_t RecordsAffected;
    try
    {
        m_pConnection->Execute( (_bstr_t)sql, &RecordsAffected, adCmdText);
        return TRUE;
    }
    catch(_com_error e )
    {
        AfxMessageBox( _T("执行SQL语句错误！") );
        return FALSE;
    }
}

5、关闭记录集

//关闭记录集
BOOL CDbOpe::CloseTable()
{
    if( m_pRecordset->State)
        m_pRecordset->Close();
    m_pRecordset = NULL;
    return TRUE;
}

6、关闭连接

//关闭连接
BOOL CDbOpe::CloseLink()
{
    CloseTable();
    if(m_pConnection->State)
         m_pConnection->Close();
    m_pConnection = NULL;
    return TRUE;
}

7、释放COM资源

CoUninitialize();

8读取表数据相关代码

//判断打开的记录集是否到了最后一行
BOOL CDbOpe::IsTalbeEnd()
{
    if( m_pRecordset->adoEOF )
        return TRUE;
    else
        return FALSE;
}
//向下一条移动
BOOL CDbOpe::MoveNext()
{
    if( !m_pRecordset->adoEOF )
    {
        m_pRecordset->MoveNext();
        return TRUE;
    }
    else
    {
        return FALSE;
    }
}
//取得字符串值
CString CDbOpe::GetStringValue(CString colName)
{
    CString strReturnValue = _T("");
    _variant_t var = m_pRecordset->GetCollect( (_bstr_t)colName );
    if(var.vt != VT_NULL)
        strReturnValue = (LPCSTR)_bstr_t(var);
    strReturnValue.TrimRight();     //移除右侧的空格
    return strReturnValue;
}