如何使用PHP同步两个数据库表? [英] How can i synchronize two database tables with PHP?

问题描述

我需要使用PHP将数据从一个MySQL数据库复制到另一个数据库.

I need to use PHP to copy data from one MySQL database to another.

我可以构建所有数组的值并将它们放入另一个数据库中，但是首先我要确保数据库在插入之前具有正确的字段.

I can build and array of all the values to go into the other database but first I want to make sure the database has the correct fields before inserting.

例如说我要从表A复制数据到表B.

For example say I am going to be copying data from tableA to tableB.

我可以将tableB设置为类似于tableA，但是将来我可能会将列添加到tableA中，而忘记将它们添加到tableB中，那么我的PHP脚本将尝试将数据插入到tableB中不存在的列中它将失败.

I can set up tableB to look just like tableA but in the future I may add columns to tableA and forget to add them to tableB, then my PHP script will try to insert data into a column that doesn't exist in tableB and it will fail.

所以我要做的是将tableA与tableB进行比较，而tableA具有该tableB的任何列都没有将它们添加到tableB.

So what I want to do is compare tableA to tableB and any columns that tableA has that tableB doesn't have add them to tableB.

谁能告诉我该怎么做?

推荐答案

感谢大家，基于您的所有帮助，我编写了一个PHP类，该类将表A中的所有列复制到表B(如果它们尚不存在):

Thanks everyone, based on all your help I was able to write a PHP class that copies any columns from table A to table B if they are not already there:

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 $qry.'<br><br>';
            }
            else
            {
                mysql_query($qry) or die(mysql_error());
            }
        }
    }

    /**
     * End of Class
     */
}

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