2014年09月11日 17:21:59

如何实现PHP导出MySQL数据库

作者: 
本文提供一个封装的PHP类文件,它实现PHP导出MySQL数据库的功能。
<?php
/**
 * @author 至尊王者
 * @author Link http://home.cnblogs.com/u/flying_bat/
 * @developer Zjmainstay
 * @developer Link http://www.zjmainstay.cn
 * @usage
 * MysqlDump::dbDump('localhost', 'zjmainstay', '', 'test', 't_trade', 'tmp.sql');
 */
class MysqlDump {
    /**
     * 数据库内容导出
     * @param $host         database host
     * @param $user         username
     * @param $pwd          password
     * @param $db           database name
     * @param $table        only dump one table
     * @param $filename     custom file to write output content
     */
    public static function dbDump($host, $user, $pwd, $db, $table = null, $filename = null) {
        $mysqlconlink = mysql_connect($host, $user, $pwd, true);
        if (!$mysqlconlink)
            echo sprintf('No MySQL connection: %s',mysql_error())."<br/>";
        mysql_set_charset( 'utf8', $mysqlconlink );
        $mysqldblink = mysql_select_db($db,$mysqlconlink);
        if (!$mysqldblink)
            echo sprintf('No MySQL connection to database: %s',mysql_error())."<br/>";
        $tabelstobackup = array();
        $result = mysql_query("SHOW TABLES FROM `$db`");
        if (!$result)
            echo sprintf('Database error %1$s for query %2$s', mysql_error(), "SHOW TABLE STATUS FROM `$db`;")."<br/>";
        while ($data = mysql_fetch_row($result)) {
            if(empty($table)) {
                $tabelstobackup[] = $data[0];
            } else if(strtolower($data[0]) == strtolower($table)){  //only dump one table
                $tabelstobackup[] = $data[0];
                break;
            }
        }
        if (count($tabelstobackup)>0) {
            $result=mysql_query("SHOW TABLE STATUS FROM `$db`");
            if (!$result)
                echo sprintf('Database error %1$s for query %2$s', mysql_error(), "SHOW TABLE STATUS FROM `$db`;")."<br/>";
            while ($data = mysql_fetch_assoc($result)) {
                $status[$data['Name']]=$data;
            }
            if(!isset($filename)) {
                $date = date('YmdHis');
                $filename = "{$db}.{$date}.sql";
            }
            if ($file = fopen($filename, 'wb')) {
                fwrite($file, "-- ---------------------------------------------------------\n");
                fwrite($file, "-- Database Name: $db\n");
                if(empty($table)) {    //if not only dump single table, dump database create sql 
                    self::_db_dump_create_database($db, $file);
                }
                fwrite($file, "-- ---------------------------------------------------------\n\n");
                fwrite($file, "/*!40101 SET @OLD_CHARACTER_SET_CLIENT=@@CHARACTER_SET_CLIENT */;\n");
                fwrite($file, "/*!40101 SET @OLD_CHARACTER_SET_RESULTS=@@CHARACTER_SET_RESULTS */;\n");
                fwrite($file, "/*!40101 SET @OLD_COLLATION_CONNECTION=@@COLLATION_CONNECTION */;\n");
                fwrite($file, "/*!40101 SET NAMES '".mysql_client_encoding()."' */;\n");
                fwrite($file, "/*!40103 SET @OLD_TIME_ZONE=@@TIME_ZONE */;\n");
                fwrite($file, "/*!40103 SET TIME_ZONE='".mysql_result(mysql_query("SELECT @@time_zone"),0)."' */;\n");
                fwrite($file, "/*!40014 SET @OLD_UNIQUE_CHECKS=@@UNIQUE_CHECKS, UNIQUE_CHECKS=0 */;\n");
                fwrite($file, "/*!40014 SET @OLD_FOREIGN_KEY_CHECKS=@@FOREIGN_KEY_CHECKS, FOREIGN_KEY_CHECKS=0 */;\n");
                fwrite($file, "/*!40101 SET @OLD_SQL_MODE=@@SQL_MODE, SQL_MODE='NO_AUTO_VALUE_ON_ZERO' */;\n");
                fwrite($file, "/*!40111 SET @OLD_SQL_NOTES=@@SQL_NOTES, SQL_NOTES=0 */;\n\n");
                foreach($tabelstobackup as $table) {
                    echo sprintf('Dump database table "%s"',$table)."<br/>";
                    self::need_free_memory(($status[$table]['Data_length']+$status[$table]['Index_length'])*3);
                    self::_db_dump_table($table,$status[$table],$file);
                }
                fwrite($file, "\n");
                fwrite($file, "/*!40103 SET TIME_ZONE=@OLD_TIME_ZONE */;\n");
                fwrite($file, "/*!40101 SET SQL_MODE=@OLD_SQL_MODE */;\n");
                fwrite($file, "/*!40014 SET FOREIGN_KEY_CHECKS=@OLD_FOREIGN_KEY_CHECKS */;\n");
                fwrite($file, "/*!40014 SET UNIQUE_CHECKS=@OLD_UNIQUE_CHECKS */;\n");
                fwrite($file, "/*!40101 SET CHARACTER_SET_CLIENT=@OLD_CHARACTER_SET_CLIENT */;\n");
                fwrite($file, "/*!40101 SET CHARACTER_SET_RESULTS=@OLD_CHARACTER_SET_RESULTS */;\n");
                fwrite($file, "/*!40101 SET COLLATION_CONNECTION=@OLD_COLLATION_CONNECTION */;\n");
                fwrite($file, "/*!40111 SET SQL_NOTES=@OLD_SQL_NOTES */;\n");
                fclose($file);
                echo 'Database dump done!'."<br/>";
            } else {
                echo 'Can not create database dump!'."<br/>";
            }
        } else {
            echo 'No tables to dump'."<br/>";
        }
    }

    protected static function _db_dump_create_database($dbname, $file) {
        $sql = "SHOW CREATE DATABASE `".$dbname."`";
        $result=mysql_query($sql);
        if (!$result) {
            echo sprintf('Database error %1$s for query %2$s', mysql_error(), $sql)."<br/>";
            return false;
        }
        $dbstruc=mysql_fetch_assoc($result);
        fwrite($file, str_ireplace('CREATE DATABASE', 'CREATE DATABASE IF NOT EXISTS', $dbstruc['Create Database']).";\n");
        fwrite($file, "USE `{$dbname}`;\n");
    }

    protected static function _db_dump_table($table,$status,$file) {
        fwrite($file, "\n");
        fwrite($file, "--\n");
        fwrite($file, "-- Table structure for table $table\n");
        fwrite($file, "--\n\n");
        fwrite($file, "DROP TABLE IF EXISTS `" . $table .  "`;\n");
        fwrite($file, "/*!40101 SET @saved_cs_client     = @@character_set_client */;\n");
        fwrite($file, "/*!40101 SET character_set_client = '".mysql_client_encoding()."' */;\n");
        $result=mysql_query("SHOW CREATE TABLE `".$table."`");
        if (!$result) {
            echo sprintf('Database error %1$s for query %2$s', mysql_error(), "SHOW CREATE TABLE `".$table."`")."<br/>";
            return false;
        }
        $tablestruc=mysql_fetch_assoc($result);
        fwrite($file, $tablestruc['Create Table'].";\n");
        fwrite($file, "/*!40101 SET character_set_client = @saved_cs_client */;\n");
        $result=mysql_query("SELECT * FROM `".$table."`");
        if (!$result) {
            echo sprintf('Database error %1$s for query %2$s', mysql_error(), "SELECT * FROM `".$table."`")."<br/>";
            return false;
        }
        fwrite($file, "--\n");
        fwrite($file, "-- Dumping data for table $table\n");
        fwrite($file, "--\n\n");
        if ($status['Engine']=='MyISAM')
            fwrite($file, "/*!40000 ALTER TABLE `".$table."` DISABLE KEYS */;\n");
        while ($data = mysql_fetch_assoc($result)) {
            $keys = array();
            $values = array();
            foreach($data as $key => $value) {
                if($value === NULL)
                    $value = "NULL";
                elseif($value === "" or $value === false)
                    $value = "''";
                elseif(!is_numeric($value))
                    $value = "'".mysql_real_escape_string($value)."'";
                $values[] = $value;
            }
            fwrite($file, "INSERT INTO `".$table."` VALUES ( ".implode(", ",$values)." );\n");
        }
        if ($status['Engine']=='MyISAM')
            fwrite($file, "/*!40000 ALTER TABLE ".$table." ENABLE KEYS */;\n");
    }
    protected static function need_free_memory($memneed) {
        if (!function_exists('memory_get_usage'))
            return;
        $needmemory=@memory_get_usage(true) + self::inbytes($memneed);
        if ($needmemory > self::inbytes(ini_get('memory_limit'))) {
            $newmemory=round($needmemory/1024/1024)+1 .'M';
            if ($needmemory>=1073741824)
                $newmemory=round($needmemory/1024/1024/1024) .'G';
            if ($oldmem=@ini_set('memory_limit', $newmemory))
                echo sprintf('Memory increased from %1$s to %2$s','backwpup',$oldmem,@ini_get('memory_limit'))."<br/>";
            else
                echo sprintf('Can not increase memory limit is %1$s','backwpup',@ini_get('memory_limit'))."<br/>";
        }
    }
    
    protected static function inbytes($value) {
        $multi = strtoupper(substr(trim($value), -1));
        $bytes = abs((int)trim($value));
        if ($multi=='G')
            $bytes=$bytes*1024*1024*1024;
        if ($multi=='M')
            $bytes=$bytes*1024*1024;
        if ($multi=='K')
            $bytes=$bytes*1024;
        return $bytes;
    }
}

文件源码:http://demo.zjmainstay.cn/php/class/MysqlDump.class.php?source

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