php数据库操作类代码(增,删,改,查)

class mysql {

private $db_host; //数据库主机
private $db_user; //数据库登陆名
private $db_pwd; //数据库登陆密码
private $db_name; //数据库名
private $db_charset; //数据库字符编码
private $db_pconn; //长连接标识位
private $debug; //调试开启
private $conn; //数据库连接标识
private $msg = ""; //数据库操纵信息

// private $sql = ""; //待执行的SQL语句

public function __construct($db_host, $db_user, $db_pwd, $db_name, $db_chaeset = 'utf8', $db_pconn = false, $debug = false) {
$this->db_host = $db_host;
$this->db_user = $db_user;
$this->db_pwd = $db_pwd;
$this->db_name = $db_name;
$this->db_charset = $db_chaeset;
$this->db_pconn = $db_pconn;
$this->result = '';
$this->debug = $debug;
$this->initConnect();
}

public function initConnect() {
if ($this->db_pconn) {
$this->conn = @mysql_pconnect($this->db_host, $this->db_user, $this->db_pwd);
} else {
$this->conn = @mysql_connect($this->db_host, $this->db_user, $this->db_pwd);
}
if ($this->conn) {
$this->query("SET NAMES " . $this->db_charset);
} else {
$this->msg = "数据库连接出错，错误编号：" . mysql_errno() . "错误原因：" . mysql_error();
}
$this->selectDb($this->db_name);
}

public function selectDb($dbname) {
if ($dbname == "") {
$this->db_name = $dbname;
}
if (!mysql_select_db($this->db_name, $this->conn)) {
$this->msg = " 数据库不可用";
}
}

public function query($sql, $debug = false) {
if (!$debug) {
$this->result = @mysql_query($sql, $this->conn);
} else {

}
if ($this->result == false) {
$this->msg = "sql执行出错，错误编号：" . mysql_errno() . "错误原因：" . mysql_error();
}
// var_dump($this->result);
}

public function select($tableName, $columnName = "*", $where = "") {
$sql = "SELECT " . $columnName . " FROM " . $tableName;
$sql .= $where ? " WHERE " . $where : null;
$this->query($sql);
}

public function findAll($tableName) {
$sql = "SELECT * FROM $tableName";
$this->query($sql);
}

public function insert($tableName, $column = array()) {
$columnName = "";
$columnValue = "";
foreach ($column as $key => $value) {
$columnName .= $key . ",";
$columnValue .= "'" . $value . "',";
}
$columnName = substr($columnName, 0, strlen($columnName) - 1);
$columnValue = substr($columnValue, 0, strlen($columnValue) - 1);
$sql = "INSERT INTO $tableName($columnName) VALUES($columnValue)";
$this->query($sql);
if($this->result){
$this->msg = "数据插入成功。新插入的id为：" . mysql_insert_id($this->conn);
}
}

public function update($tableName, $column = array(), $where = "") {
$updateValue = "";
foreach ($column as $key => $value) {
$updateValue .= $key . "='" . $value . "',";
}
$updateValue = substr($updateValue, 0, strlen($updateValue) - 1);
$sql = "UPDATE $tableName SET $updateValue";
$sql .= $where ? " WHERE $where" : null;
$this->query($sql);
if($this->result){
$this->msg = "数据更新成功。受影响行数：" . mysql_affected_rows($this->conn);
}
}

public function delete($tableName, $where = ""){
$sql = "DELETE FROM $tableName";
$sql .= $where ? " WHERE $where" : null;
$this->query($sql);
if($this->result){
$this->msg = "数据删除成功。受影响行数：" . mysql_affected_rows($this->conn);
}
}

public function fetchArray($result_type = MYSQL_BOTH){
$resultArray = array();
$i = 0;
while($result = mysql_fetch_array($this->result, $result_type)){
$resultArray[$i] = $result;
$i++;
}
return $resultArray;
}

// public function fetchObject(){
// return mysql_fetch_object($this->result);
// }

public function printMessage(){
return $this->msg;
}

public function freeResult(){
@mysql_free_result($this->result);
}

public function __destruct() {
if(!empty($this->result)){
$this->freeResult();
}
mysql_close($this->conn);
}
}