Mysql read and write separation implemented by PHP

Author：Eve Cole Update Time：2009-06-07 15:14:46

This code is modified from the uchome code and is processed to solve the efficiency of uchome.
The encapsulation method is relatively simple, adding an interface extension for read-only database connection, and not using a read-only database does not affect the use of the original code.
It remains to be continuously improved in the future. .

For convenience, try setting up a Google project:
http://code.google.com/p/mysql-rw-php/Hope

to help friends in need.

The main features

of Mysql read-write separation implemented by PHP

simple read-write separation of a main database, you can add more read-only databases, but don't worry about some features not supported. Disadvantages: connecting two databases at the same time, the English is poor, and Write a few words

php code for mysql read/write split
feature:
simply rw split
one master,can add more slaves
support all mysql feature
link to the master and slave at the same time

PHP code:

mysql_rw_php.class.php

<?php
/******************************************
*** mysql-rw-php version 0.1 @ 2009-4-16
*** code by hqlulu#gmail.com
*** http://www.aslibra.com
*** http://code.google.com/p/mysql-rw-php/
*** code modify from class_mysql.php (uchome)
******************************************/
class mysql_rw_php {
//Query the number
var $querynum = 0;
//Database connection for current operation
var $link = null;
//Character set
var $charset;
//Current database
var $cur_db = ";
//Whether there is a valid read-only database connection
var $ro_exist = false;
//read-only database connection
var $link_ro = null;
//Read and write database connection
var $link_rw = null;
function mysql_rw_php(){
}
function connect($dbhost, $dbuser, $dbpw, $dbname = ”, $pconnect = 0, $halt = TRUE) {
if($pconnect) {
if(!$this->link = @mysql_pconnect($dbhost, $dbuser, $dbpw)) {
$halt && $this->halt('Can not connect to MySQL server');
}
} else {
if(!$this->link = @mysql_connect($dbhost, $dbuser, $dbpw)) {
$halt && $this->halt('Can not connect to MySQL server');
}
}

//Read-only connection failed
if(!$this->link && !$halt) return false;

//When rw is not initialized, the first connection is used as rw
if($this->link_rw == null)
$this->link_rw = $this->link;
if($this->version() > '4.1′) {
if($this->charset) {
@mysql_query("SET character_set_connection=$this->charset, character_set_results=$this->charset, character_set_client=binary", $this->link);
}
if($this->version() > '5.0.1′) {
@mysql_query(”SET sql_mode=””, $this->link);
}
}
if($dbname) {
$this->select_db($dbname);
}
}
//http://www.knowsky.com/php.asp Connect to a read-only mysql database
function connect_ro($dbhost, $dbuser, $dbpw, $dbname = ”, $pconnect = 0){
if($this->link_rw == null)
$this->link_rw = $this->link;
$this->link = null;
//Do not generate halt error
$this->connect($dbhost, $dbuser, $dbpw, $dbname, $pconnect, false);
if($this->link){
//Connection successful
//echo “link ro sussess! ”;
$this->ro_exist = true;
$this->link_ro = $this->link;
if($this->cur_db){
//If you have already selected the database, you need to operate it once
@mysql_select_db($this->cur_db, $this->link_ro);
}
}else{
//Connection failed
//echo “link ro failed! ”;
$this->link = &$this->link_rw;
}
}
//Set up a series of read-only databases and connect to one of them
function set_ro_list($ro_list){
if(is_array($ro_list)){
//Randomly select one of them
$link_ro = $ro_list[array_rand($ro_list)];
$this->connect_ro($link_ro['dbhost'], $link_ro['dbuser'], $link_ro['dbpw']);
}
}
function select_db($dbname) {
//Operate two database connections at the same time
$this->cur_db = $dbname;
if($this->ro_exist){
@mysql_select_db($dbname, $this->link_ro);
}
return @mysql_select_db($dbname, $this->link_rw);
}
function fetch_array($query, $result_type = MYSQL_ASSOC) {
return mysql_fetch_array($query, $result_type);
}
function fetch_one_array($sql, $type = ”) {
$qr = $this->query($sql, $type);
return $this->fetch_array($qr);
}
function query($sql, $type = ”) {
$this->link = &$this->link_rw;
//Determine whether to select the statement
if($this->ro_exist && preg_match ("/^(s*)select/i", $sql)){
$this->link = &$this->link_ro;
}
$func = $type == 'UNBUFFERED' && @function_exists('mysql_unbuffered_query') ?
'mysql_unbuffered_query' : 'mysql_query';
if(!($query = $func($sql, $this->link)) && $type != 'SILENT') {
$this->halt('MySQL Query Error', $sql);
}
$this->querynum++;
return $query;
}
function affected_rows() {
return mysql_affected_rows($this->link);
}
function error() {
return (($this->link) ? mysql_error($this->link) : mysql_error());
}
function errno() {
return intval(($this->link) ? mysql_errno($this->link) : mysql_errno());
}
function result($query, $row) {
$query = @mysql_result($query, $row);
return $query;
}
function num_rows($query) {
$query = mysql_num_rows($query);
return $query;
}
function num_fields($query) {
return mysql_num_fields($query);
}
function free_result($query) {
return mysql_free_result($query);
}
function insert_id() {
return ($id = mysql_insert_id($this->link)) >= 0 ? $id : $this->result($this->query("SELECT last_insert_id()"), 0);
}
function fetch_row($query) {
$query = mysql_fetch_row($query);
return $query;
}
function fetch_fields($query) {
return mysql_fetch_field($query);
}
function version() {
return mysql_get_server_info($this->link);
}
function close() {
return mysql_close($this->link);
}
function halt($message = ”, $sql = ”) {
$dberror = $this->error();
$dberrno = $this->errno();
echo “<div style=”position:absolute;font-size:11px;font-family:verdana,arial;background:#EBEBEB;padding:0.5em;”>
MySQL Error 
Message: $message 
SQL: $sql 
Error: $dberror 
Errno.: $dberrno 
</div>";
exit();
}
}
?>
example.php