A database operation PHP class

 /*
 * Author Molong
 * Time December 2, 2010 15:50:35
 */

 $db = new mysql($db_host,$db_user,$db_password, $db_table,$db_conn,$pre,$coding);

 class mysql{

 private $db_host;
 private $db_user;
 private $db_password;
 private $db_table;
 private $db_conn; //Database connection identification;
 private $result; //Result resource identification of executing query command
 private $sql; //SQL execution statement
 private $pre; //Database table prefix
 private $coding; //Database encoding, GBK, UTF8, gb2312

 function __construct($db_host,$db_user,$db_password,$db_table,$db_conn,$pre,$coding){

 $this->db_host = $db_host;
 $this->db_user = $db_user;
 $this->db_password = $db_password;
 $this->db_table = $db_table;
 $this->db_conn = $db_conn;
 $this->pre = $pre;
 $this->coding = $coding;
 $this->connect();

 }

 function connect(){

 $this->db_conn = @mysql_connect($this->db_host,$this->db_user, $this->db_password) or die($this->show_error("Database link error, please check the database link configuration! "));
 if(!mysql_select_db($this->db_table,$this->db_conn)){

 echo "Data table not found: ".$this->db_table;
 }
 mysql_select_db($ this->db_table,$this->db_conn);
 $this->query("SET NAMES $this->coding");
 }

 /*Function to execute SQL statements*/
 function query ($sql){

 if(emptyempty($sql)){
 $this->show_error("Your sql statement cannot be empty!");
 }else{
 $this->sql = $sql;
 }
 $result = mysql_query($this->sql,$this->db_conn);

 return $this->result = $result;
 }

 /*Create and add a new database*/
 public function create_database($database_name){
 $database=$database_name;
 $sqlDatabase = 'create database '.$database;
 return $this- >query($sqlDatabase);
 }

 // Calculate the number of result set items based on the select query results
 public function db_num_rows(){
 if($this->result==null){
 if($this- >show_error){
 $this->show_error("sql statement error!");
 }
 }else{
 return mysql_num_rows($this->result);
 }
 }

 /*Query all server Database*/
 //Separate the system database and the user database for a more intuitive display?
 public function show_databases(){
 $this->query("show databases");
 echo "Existing database:".$ amount =$this->db_num_rows($rs);
 echo "";
 $i=1;
 while($row = $this->fetch_array($rs)){
 echo "$i $row[Database]";
 echo "";
 $i++;
 }
 }

 //Return all database names in the host in array form
 public function databases()
 {
 $rsPtr=mysql_list_dbs($this->db_conn);
 $i=0;
 $cnt=mysql_num_rows($rsPtr);
 while($i<$cnt)
 {
 $rs[]=mysql_db_name($ rsPtr,$i);
 $i++;
 }
 return print_r($rs);
 }

 /*Query all tables under the database*/
 function show_tables($database_name){
 $this->query( "show tables");
 echo "Existing database:".$amount = $this->db_num_rows($rs);
 echo "";
 $i=1;
 while($ row = $this->fetch_array($rs)){
 $columnName="Tables_in_".$database_name;
 echo "$i $row[$columnName]";
 echo "";
 $i++;
 }
 }

 /*
 mysql_fetch_row() array $row[0],$row[1],$row[2]
 mysql_fetch_array() array $row[0] or $row[id]
 mysql_fetch_assoc() array uses $row->content field case sensitivity
 mysql_fetch_object() object uses $row[id],$row[content] fields case sensitivity
 */
 /*Get the record set, get the array-index and association, use $row['content'] */
 public function fetch_array()
 {
 return @mysql_fetch_array($this->result);
 }

 //Get the association array, use $row[' field name']
 public function fetch_ass()
 {
 return @mysql_fetch_assoc($this->result);
 }

 //Get the numeric index array, use $row[0],$row[1],$row [2]
 public function fetch_row()
 {
 return @mysql_fetch_row($this->result);
 }

 //Get the object array, use $row->content
 public function fetch_Object()
 {
 return @mysql_fetch_object($this->result);
 }

 //Simplified query select
 public function findall($table){
 $table = $this->fulltablename($table);
 $this-> ;query("select * from $table");
 }

 public function select($table,$columnName,$condition){
 $table = $this->fulltablename($table);
 if(emptyempty( $columnName)){
 $columnName = "*";
 }
 $this->query("SELECT $columnName FROM $table $condition");
 }

 //Simplified insert
 function insert($table ,$arr){
 $table = $this->fulltablename($table);
 $sql = "INSERT INTO $table ";
 if(!is_array($arr)){
 $this->show_error( "Please enter the parameter array!");
            }else{
            $k = "";
            $v = "";
            foreach($arr as $key => $value){
                $k .= "`$key`,";
                $v .= "'".$value."',";
            }
            }
            $sql = $sql." (".substr($k,0,-1).") VALUES (".substr($v,0,-1).")";
            $this->query($sql);
        }
        //简化的update
        function update($table,$arr,$where){
            $table = $this->fulltablename($table);
            $sql = "UPDATE $table SET ";
            if(!is_array($arr)){
                $this->show_error("请输入参数数组！");
 }else{
 foreach($arr as $key => $value){
 $sql .= " `".$key."` = '".$value."' ,";
 }
 }
 $sql = substr($sql,0,-1)." where ".$where;
 return $this->query($sql);
 }
 //Simplified delete
 function delete($ table,$where = ""){
 $table = $this->fulltablename($table);
 if(emptyempty($where)){
 $this->show_error("Condition cannot be empty!") ;
 }else{
 $where = " where ".$where;
 }
 $sql = "DELETE FROM $table ".$where;
 //echo $sql;
 return $this->query($sql );
 }

 //Get the ID generated by the previous INSERT operation
 public function insert_id(){
 return mysql_insert_id();
 }

 //Prefixed data table
 public function fulltablename($table){
 return $table = $this->pre.$table;
 }

 //Query the number of fields
 public function num_fields($table){
 $table = $this->fulltablename($table);
 $ this->query("select * from $table");
 echo "";
 echo "Number of fields: ".$total = mysql_num_fields($this->result);
 echo " ";
 for ($i=0; $i<$total; $i++){
 print_r(mysql_fetch_field($this->result,$i) );
 }
 echo "
 echo "";
 }

 //Get MySQL server information
 public function mysql_server($num=''){
 switch ($num){
 case 1:
 return mysql_get_server_info (); //MySQL server information
 break;

 case 2 :
 return mysql_get_host_info(); //Get MySQL host information
 break;

 case 3 :
 return mysql_get_client_info(); //Get MySQL client information
 break;

 case 4:
 return mysql_get_proto_info(); //Get MySQL protocol information
 break;

 default:
 return mysql_get_client_info(); //Get mysql version information by default
 }
 }

 //Destructor , automatically close the database, garbage collection mechanism
 /*public function __destruct()
 {
 if(!empty($this->result)){
 $this->free();
 }
 mysql_close($this ->$db_conn);
 }*/

 /*Get the real IP address of the client*/
 function getip(){
 if(getenv("HTTP_CLIENT_IP") && strcasecmp(getenv("HTTP_CLIENT_IP"), " unknown"))
 {
 $ip = getenv("HTTP_CLIENT_IP");
 }
 else if (getenv("HTTP_X_FORWARDED_FOR") && strcasecmp(getenv("HTTP_X_FORWARDED_FOR"), "unknown")){
 $ip = getenv ("HTTP_X_FORWARDED_FOR");
 }
 else if (getenv("REMOTE_ADDR") && strcasecmp(getenv("REMOTE_ADDR"), "unknown"))
 {
 $ip = getenv("REMOTE_ADDR");
 }
 else if (isset($_SERVER['REMOTE_ADDR']) && $_SERVER['REMOTE_ADDR'] && strcasecmp($_SERVER['REMOTE_ADDR'], "unknown")){
 $ip = $_SERVER['REMOTE_ADDR'];
 }
 else{
 $ip = "unknown";
 }
 return($ip);
 }

 function show_error($str){
 echo "";
 }

 }
 ?>

PHP