一个php Mysql类 可以参考学习熟悉下

<?php
class mysql
{
private $conn;
private $host;
private $username;
private $password;
private $dbname;
private $pconnect;
private $charset;

public function __construct(array $params = null)
{
if (!empty($params)) {
foreach ($params as $k => $v) {
$this->$k = $v;
}
}
}

public function connect()
{
$fun = $this->pconnect ? 'mysql_pconnect' : 'mysql_connect';
$this->conn = $fun($this->host, $this->username, $this->password);
$this->conn && $this->query('set names ' . $this->charset);
$this->conn && mysql_select_db($this->dbname, $this->conn);
}

public function getinstance()
{
return $this->conn;
}

public function query($sql)
{
return mysql_query($sql, $this->conn);
}

public function fetchone($sql)
{
$data = $this->fetchrow($sql);
return $data[0];
}

public function fetchcol($sql)
{
$tmp = $this->fetchall($sql, mysql_num);
foreach ($tmp as $v) {
$data[] = $v[0];
}
}

public function fetchrow($sql)
{
$result = $this->query($sql);
$data = mysql_fetch_row($result);
mysql_free_result($result);
return $data;
}

public function fetchassoc($sql)
{
$result = $this->query($sql);
$data = mysql_fetch_assoc($result);
mysql_free_result($result);
return $data;
}

public function fetchall($sql, $type = mysql_assoc)
{
$result = $this->query($sql);
while ($tmp = mysql_fetch_array($result, $type)) {
$data[] = $tmp;
}
return $data;
}

public function fetchpairs($sql)
{
$result = $this->query($sql);
while ($tmp = mysql_fetch_row($result)) {
$data[$tmp[0]] = $tmp[1];
}
return $data;

}

public function insert($table, array $bind)
{
$cols = array();
$vals = array();
foreach ($bind as $col => $val) {
$cols[] = $col;
$vals[] = $val;
unset($bind[$col]);
}
$sql = "insert into "
. $table
. ' (`' . implode('`, `', $cols) . '`) '
. 'values (\'' . implode('\', \'', $vals) . '\')';

$stmt = $this->query($sql, $this->conn);
$result = $this->affectedrows();
return $result;
}

public function getlastinsertid()
{
return mysql_insert_id($this->conn);
}

public function affectedrows()
{
return mysql_affected_rows($this->conn);
}

public function update($table, array $bind, $where = '')
{
$set = array();
foreach ($bind as $col => $val) {
$set[] = '`' . $col . "` = '" . $val . "'";
}

$sql = "update `"
. $table
. '` set ' . implode(', ', $set)
. (($where) ? " where $where" : '');

$stmt = $this->query($sql, array_values($bind));
$result = $this->affectedrows();
return $result;
}

public function delete($table, $where = '')
{
/**
* build the delete statement
*/
$sql = "delete from "
. $table
. (($where) ? " where $where" : '');

/**
* execute the statement and return the number of affected rows
*/
$stmt = $this->query($sql);
$result = $stmt ? mysql_affected_rows($this->conn) : $stmt;
return $result;
}

public function close()
{
$this->conn && mysql_close($this->conn);
}
}
?>