如何使用PHP同步两个数据库表？

我需要使用PHP将数据从一个MySQL数据库复制到另一个MySQL数据库.

我可以构建所有值的数组并将其放入另一个数据库,但首先我要确保数据库在插入之前具有正确的字段.

例如,假设我要将数据从tableA复制到tableB.

我可以设置tableB看起来就像tableA但是将来我可能会向tableA添加列而忘记将它们添加到tableB,然后我的PHP脚本将尝试将数据插入到tableB中不存在的列中它将会失败.

所以我想要做的是将tableA与tableB进行比较,以及tableA具有的任何列,tableB没有将它们添加到tableB.

谁能告诉我怎么做？

感谢大家,基于你的所有帮助,我能够编写一个PHP类,它将表A中的任何列复制到表B(如果它们还不存在):

class MatchTable 
{
    var $_table_one_name;
    var $_table_two_name;

    var $_table_one_db_user;
    var $_table_one_db_pass;
    var $_table_one_db_host;
    var $_table_one_db_name;

    var $_table_two_db_user;
    var $_table_two_db_pass;
    var $_table_two_db_host;
    var $_table_two_db_name;

    var $_table_one_columns = array();
    var $_table_two_columns = array();
    var $_table_one_types = array();
    var $_table_two_types = array();

    var $_table_one_link;
    var $_table_two_link;

    var $_isTest;


    function MatchTable($isLive = true)
    {
        $this->_isTest = !$isLive;
    }

    function matchTables($table1, $table2)
    {
        $this->_table_one_name = $table1;
        $this->_table_two_name = $table2;

        if(isset($this->_table_one_db_pass))
        {
            $this->db_connect('ONE');
        }
        list($this->_table_one_columns,$this->_table_one_types) = $this->getColumns($this->_table_one_name);

        if(isset($this->_table_two_db_pass))
        {
            $this->db_connect('TWO');
        }
        list($this->_table_two_columns,$this->_table_two_types) = $this->getColumns($this->_table_two_name);

        $this->addAdditionalColumns($this->getAdditionalColumns());
    }

    function setTableOneConnection($host, $user, $pass, $name)
    {
        $this->_table_one_db_host = $host;
        $this->_table_one_db_user = $user;
        $this->_table_one_db_pass = $pass;
        $this->_table_one_db_name = $name;
    }

    function setTableTwoConnection($host, $user, $pass, $name)
    {
        $this->_table_two_db_host = $host;
        $this->_table_two_db_user = $user;
        $this->_table_two_db_pass = $pass;
        $this->_table_two_db_name = $name;
    }

    function db_connect($table)
    {
        switch(strtoupper($table))
        {
            case 'ONE':
                $host = $this->_table_one_db_host;
                $user = $this->_table_one_db_user;
                $pass = $this->_table_one_db_pass;
                $name = $this->_table_one_db_name;
                $link = $this->_table_one_link = mysql_connect($host, $user, $pass, true);
                mysql_select_db($name) or die(mysql_error());
            break;
            case 'TWO';
                $host = $this->_table_two_db_host;
                $user = $this->_table_two_db_user;
                $pass = $this->_table_two_db_pass;
                $name = $this->_table_two_db_name;
                $link = $this->_table_two_link = mysql_connect($host, $user, $pass, true);
                mysql_select_db($name) or die(mysql_error());
            break;
            default:
                die('Improper parameter in MatchTable->db_connect() expecting "one" or "two".');
            break;
        }
        if (!$link) {
            die('Could not connect: ' . mysql_error());
        }
    }

    function getColumns($table_name)
    {
        $columns = array();
        $types = array();
        $qry = 'SHOW COLUMNS FROM '.$table_name;
        $result = mysql_query($qry) or die(mysql_error());
        while($row = mysql_fetch_assoc($result))
        {
            $field = $row['Field'];
            $type = $row['Type'];
            /*
            $column = array('Field' => $field, 'Type' => $type);
            array_push($columns, $column);
            */
            $types[$field] = $type;
            array_push($columns, $field);
        }
        $arr = array($columns, $types);
        return $arr;
    }

    function getAdditionalColumns()
    {
        $additional = array_diff($this->_table_one_columns,$this->_table_two_columns);
        return $additional;
    }

    function addAdditionalColumns($additional)
    {
        $qry = '';
        foreach($additional as $field)
        {
            $qry = 'ALTER TABLE '.$this->_table_two_name.' ADD '.$field.' '.$this->_table_one_types[$field].'; ';

            if($this->_isTest)
            {
                echo $qry.'

';
            }
            else
            {
                mysql_query($qry) or die(mysql_error());
            }
        }
    }

    /**
     * End of Class
     */
}