新闻发布系统 (例子) 二 dbconn

class CDBAbstract {
var $_db_linkid = 0;
var $_db_qresult = 0;
var $RowData = array();
var $NextRowNumber = 0;
var $RowCount = 0;
function CDBAbstract () {
die ("CDBAbstract: Do not create instances of CDBAbstract! Use a subclass.");
}
function Open ($host, $user, $pass, $db = "") {
}
function Close () {
}
function SelectDB ($dbname) {
}
function Query ($querystr) {
}
function SeekRow ($row = 0) {
}
function ReadRow () {
}
function _ident () {
return "CDBAbstract/1.1";
}
}

class CDBMySQL extends CDBAbstract {
function CDBMySQL ($host, $user, $pass, $db = "") {
$this->Open ($host, $user, $pass);
if ($db != "")
$this->SelectDB($db);
}
function Open ($host, $user, $pass) {
$this->_db_linkid = mysql_connect ($host, $user, $pass);
}
function Close () {
@mysql_free_result($this->_db_qresult);
return mysql_close ($this->_db_linkid);
}
function SelectDB ($dbname) {
if (@mysql_select_db ($dbname, $this->_db_linkid) == true) {
return 1;
}
else {
return 0;
}
}
function Query ($querystr) {
$result = mysql_query ($querystr, $this->_db_linkid);
if ($result == 0) {
return 0;
}
else {
@mysql_free_result($this->_db_qresult);
$this->RowData = array();
$this->_db_qresult = $result;
$this->RowCount = @mysql_num_rows ($this->_db_qresult);
if (!$this->RowCount) {
// The query was probably an INSERT/REPLACE etc.
$this->RowCount = 0;
}
return 1;
}
}
function SeekRow ($row = 0) {
if ((!mysql_data_seek ($this->_db_qresult, $row)) or ($row > $this->RowCount-1)) {
printf ("SeekRow: Cannot seek to row %d\n", $row);
return 0;
}
else {
return 1;
}
}
function ReadRow () {
if($this->RowData = mysql_fetch_array ($this->_db_qresult)) {
$this->NextRowNumber++;
return 1;
}
else {
return 0;
}
}
function _ident () {
return "CDBMySQL/1.1";
}
}

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