php的一个数据库操纵类的详细介绍

以下是我在工作中常用的一个php中对sql server2000中数据操纵的一个公共odbc操纵类，希望能够给各位初学php的同仁一点点帮助

<?
file://include ("odbc_para.php");
$DbName="localhost";
$DbUser="sa";
$DbPassWord="";//在这里进行定义连接odbc的数据库名，用户名，及密码，实际中以数据库的用户

file://名及密码为标准。

define(C_DB_HOST,$Host);
define(C_DB_NAME,$DbName);
define(C_DB_USER,$DbUser);
define(C_DB_PASS,$DbPassWord);

class Odbc{
var $Host = C_DB_HOST;// Hostname of our MySQL server
var $Database = C_DB_NAME;// Logical database name on that server
var $User = C_DB_USER;// Database user
var $Password = C_DB_PASS;// Database user's password
var $UseODBCCursor = 0;

var $Link_ID = 0;// Result of mysql_connect()
var $Query_ID = 0;// Result of most recent mysql_query()
// var $Record = array(); // Current mysql_fetch_array()-result
var $Row = 0;// Current row number
var $Errno = 0;// Error state of query
var $Error = "";

var $Auto_Free = 0; ## set this to 1 to automatically free results

function Halt($msg) {
printf("</td></tr></table><b>Database error:</b> %s<br>/n", $msg);
printf("<b>ODBC Error</b>: %s (%s)<br>/n",
$this->Errno,
$this->Error);
die("Session halted.");
}

function Connect() {
if ( 0 == $this->Link_ID ) {
$this->Link_ID=odbc_connect($this->Database, $this->User, $this->Password, $this->UseODBCCursor);
if (!$this->Link_ID) {
$this->halt("Link-ID == false, odbc_connect failed");
}
}
}

function Close() {
if (0 != $this->Link_ID){
odbc_close($this->Link_ID);
}
}

function Query($Query_String) {
$this->Connect();

# printf("<br>Debug: query = %s<br>/n", $Query_String);

# rei@netone.com.br suggested that we use this instead of the odbc_exec().
# He is on NT, connecting to a Unix MySQL server with ODBC. -- KK
# $this->Query_ID = odbc_prepare($this->Link_ID,$Query_String);
# $this->Query_Ok = odbc_execute($this->Query_ID);

$this->Query_ID = odbc_exec($this->Link_ID,$Query_String);
$this->Row = 0;
file://odbc_binmode($this->Query_ID, 1);
file://odbc_longreadlen($this->Query_ID, 4096000);

if (!$this->Query_ID) {
$this->Errno = 1;
$this->Error = "General Error (The ODBC interface cannot return detailed error messages).";
$this->halt("Invalid SQL: ".$Query_String);
}
return $this->Query_ID;
}

function NextRecord() {
$this->Record = array();
$this->$stat = odbc_fetch_into($this->Query_ID,&$this->Record, ++$this->Row);
if (!$this->$stat) {
if ($this->Auto_Free) {
odbc_free_result($this->Query_ID);
$this->Query_ID = 0;
};
} else {
// add to Record[<key>]
$count = odbc_num_fields($this->Query_ID);
for ($i=1; $i<=$count; $i++)
$this->Record[strtolower(odbc_field_name ($this->Query_ID, $i)) ] = stripslashes($this->Record[ $i - 1 ]);
}
return $this->Record;
}

function Seek($pos) {
$this->Row = $pos;
}

function MetaData($table) {
$count = 0;
$id = 0;
$res = array();

$this->Connect();
$id = odbc_exec($this->Link_ID, "select * form $table");
if (!$id) {
$this->Errno = 1;
$this->Error = "General Error (The ODBC interface cannot return detailed error messages).";
$this->halt("Metadata query failed.");
}
$count = odbc_num_fields($id);

for ($i=1; $i<=$count; $i++) {
$res[$i]["table"] = $table;
$name = odbc_field_name ($id, $i);
$res[$i]["name"] = $name;
$res[$i]["type"] = odbc_field_type ($id, $name);
$res[$i]["len"] = 0; // can we determine the width of this column?
$res[$i]["flags"] = ""; // any optional flags to report?
}

odbc_free_result($id);
return $res;
}

function NumRows() {
# Many ODBC drivers don't support odbc_num_rows() on SELECT statements.
$num_rows = odbc_num_rows($this->Query_ID);
file://printf ($num_rows."<br>");

# This is a workaround. It is intended to be ugly.
if ($num_rows < 0) {
$i=10;
while (odbc_fetch_row($this->Query_ID, $i))
$i*=10;

$j=0;
while ($i!=$j) {
$k= $j+intval(($i-$j)/2);
if (odbc_fetch_row($this->Query_ID, $k))
$j=$k;
else
$i=$k;
if (($i-$j)==1) {
if (odbc_fetch_row($this->Query_ID, $i))
$j=$i;
else
$i=$j;
};
file://printf("$i $j $k <br>");
};
$num_rows=$i;
}

return $num_rows;
}

function NumFields() {
return count($this->Record)/2;
}

function FieldValue($Field_Name){
return odbc_result($this->Query_ID,$Field_Name);//Record[strtolower($Field_Name)];
}

function AffectedRows() {
return odbc_num_rows($this->Query_ID);
}

}
?>

我的这个操作类是一个odbc接口类。在调用数据操作之前首先需进行odbc的连接，然后再把相应的值付给下面的变量，以便进行操纵：

$DbName="localhost";
$DbUser="sa";
$DbPassWord="";//

假设在odbc连接成功的条件下，对数据库中的表table1进行操作则如下进行：

$db=new Odbc();

$sq1="select * from $table";//选择表中的所有记录

$db->query($sql);

while($result=$db->NextRecrod)

{

echo $result;

}

$db->Close();

.

.

.