Η ανταλλαγή στηλών πίνακα SQL αποτελεί μέρος του τυπικού ρεπερτορίου με MySQL - αυτό δεν υποστηρίζεται (ακόμη) με το PostgreSQL. Παρόλο που το επίσημο wiki αφιερώνει το δικό του άρθρο στο πρόβλημα, δεν δείχνει καμία πρακτική λύση που να υποστηρίζει επίσης απόψεις, δείκτες και κανόνες. Η ακόλουθη τάξη κάνει αυτήν την εργασία (τόσο για τη MySQL όσο και για την PostgreSQL) είτε στη γραμμή εντολών - είτε εναλλακτικά απευθείας στο Laravel 5.
<?php
namespace App\Helpers;
class ColumnChanger
{
public static $quotes;
public static $path;
public static function swap($table, $col1, $col2)
{
// initialize
self::$quotes = self::getQuotes();
self::$path = self::getPath();
// export
$content = self::exportDB();
// swap
$content = self::swapNow($table, $col1, $col2, $content);
// import
self::importDB($content);
}
public static function getQuotes()
{
if (getenv("DB_CONNECTION") == "pgsql")
{
return "";
}
if (getenv("DB_CONNECTION") == "mysql")
{
return "`";
}
}
public static function getPath()
{
if (getenv("DB_CONNECTION") == "pgsql")
{
$sql = new \PDO('pgsql:host=' . getenv('DB_HOST') . ';port=' . getenv('DB_PORT') . ';dbname=' . getenv('DB_DATABASE') , getenv('DB_USERNAME') , getenv('DB_PASSWORD'));
$stmt = $sql->prepare("SHOW data_directory");
$stmt->execute();
$path = str_replace("data", "bin", $stmt->fetchObject()->data_directory) . "/";
}
if (getenv("DB_CONNECTION") == "mysql")
{
$sql = new \PDO('mysql:host=' . getenv('DB_HOST') . ';port=' . getenv('DB_PORT') . ';dbname=' . getenv('DB_DATABASE') , getenv('DB_USERNAME') , getenv('DB_PASSWORD'));
$stmt = $sql->prepare("SHOW VARIABLES LIKE 'basedir'");
$stmt->execute();
$path = $stmt->fetchObject()->Value . "bin/";
}
return $path;
}
public static function exportDB()
{
if (getenv("DB_CONNECTION") == "pgsql")
{
putenv("PGPASSWORD=" . getenv('DB_PASSWORD'));
exec('"' . self::$path . 'pg_dump" --clean --inserts -h ' . getenv('DB_HOST') . ' -p ' . getenv('DB_PORT') . ' -U ' . getenv('DB_USERNAME') . ' ' . getenv('DB_DATABASE') . ' > db.sql');
}
if (getenv("DB_CONNECTION") == "mysql")
{
exec('"' . self::$path . 'mysqldump" -h ' . getenv('DB_HOST') . ' --port ' . getenv('DB_PORT') . ' -u ' . getenv('DB_USERNAME') . ' -p"' . getenv('DB_PASSWORD') . '" ' . getenv('DB_DATABASE') . ' > db.sql');
}
return file_get_contents("db.sql");
}
public static function importDB($content)
{
file_put_contents("db.sql", $content);
if (getenv("DB_CONNECTION") == "pgsql")
{
putenv("PGPASSWORD=" . getenv('DB_PASSWORD'));
exec('"' . self::$path . 'psql" -h ' . getenv('DB_HOST') . ' -p ' . getenv('DB_PORT') . ' -U ' . getenv('DB_USERNAME') . ' -d ' . getenv('DB_DATABASE') . ' -1 -f db.sql');
}
if (getenv("DB_CONNECTION") == "mysql")
{
exec('"' . self::$path . 'mysql" -h ' . getenv('DB_HOST') . ' --port ' . getenv('DB_PORT') . ' -u ' . getenv('DB_USERNAME') . ' -p"' . getenv('DB_PASSWORD') . '" ' . getenv('DB_DATABASE') . ' --default-character-set=utf8 < db.sql');
}
unlink("db.sql");
}
public static function getPositions($haystack, $needle)
{
$positions = [];
$lastPos = 0;
while (($lastPos = strpos($haystack, $needle, $lastPos)) !== false)
{
$positions[] = $lastPos;
$lastPos = $lastPos + strlen($needle);
}
return $positions;
}
public static function getEnd($content, $begin)
{
$end = $begin;
$outside = true;
while ($outside !== true || $content[$end] != ";")
{
if ($content[$end] == "'")
{
if ($end === 0 || $content[$end - 1] != "\\")
{
$outside = !$outside;
}
}
$end++;
}
return ++$end;
}
public static function splitString($string)
{
return preg_split('/(?<!^)(?!$)/u', $string);
}
public static function getColumns($query)
{
$i = 0;
$outside = true;
$query = self::splitString($query);
foreach($query as $i => $char)
{
if ($query[$i] == "'")
{
if ($i === 0 || $query[$i - 1] != "\\")
{
$outside = !$outside;
}
}
if ($outside === true && $query[$i] == ",")
{
$query[$i] = "♥";
}
$i++;
}
$query = implode("", $query);
$cols = explode("♥", $query);
return $cols;
}
public static function swapNow($table, $col1, $col2, $content)
{
// loop through relevant statements
foreach(["CREATE TABLE " . self::$quotes . $table . self::$quotes, "INSERT INTO " . self::$quotes . $table . self::$quotes] as $skey => $statement)
{
$positions = self::getPositions($content, $statement);
foreach($positions as $position)
{
$begin = $position;
$end = self::getEnd($content, $begin);
$query_all = substr($content, $begin, $end - $begin);
$query_inside = substr($query_all, strpos($query_all, "(") + 1, strrpos($query_all, ")") - strpos($query_all, "(") - 1);
// get columns
$cols = self::getColumns($query_inside);
// get relevant column indexes
if ($skey == 0)
{
$col1pos = 0;
$col2pos = 0;
foreach($cols as $pos => $col)
{
$col = trim($col);
if (strpos($col, self::$quotes . $col1 . self::$quotes) === 0)
{
$col1pos = $pos;
}
if (strpos($col, self::$quotes . $col2 . self::$quotes) === 0)
{
$col2pos = $pos;
}
}
}
// swap columns
$tmp = $cols[$col1pos];
$cols[$col1pos] = $cols[$col2pos];
$cols[$col2pos] = $tmp;
$query_inside_new = implode(",", $cols);
// insert query into content
$query_all_new = str_replace($query_inside, $query_inside_new, $query_all);
$content = str_replace($query_all, $query_all_new, $content);
}
}
return $content;
}
}
// usage from the command line
if (isset($argv) && is_array($argv))
{
$args = [];
foreach($argv as $key => $arg)
{
switch ($arg)
{
case "-e":
$args["engine"] = $argv[$key + 1];
break;
case "-h":
$args["hostname"] = $argv[$key + 1];
break;
case "-P":
$args["port"] = $argv[$key + 1];
break;
case "-u":
$args["username"] = $argv[$key + 1];
break;
case "-p":
$args["password"] = $argv[$key + 1];
break;
case "-d":
$args["database"] = $argv[$key + 1];
break;
case "-t":
$args["table"] = $argv[$key + 1];
break;
}
}
// set default values
if (!isset($args["hostname"]))
{
$args["hostname"] = "127.0.0.1";
}
if (!isset($args["port"]) && isset($args["engine"]) && $args["engine"] == "mysql")
{
$args["port"] = "3306";
}
if (!isset($args["port"]) && isset($args["engine"]) && $args["engine"] == "pgsql")
{
$args["port"] = "5432";
}
foreach($args as $option => $arg)
{
if (!isset($arg))
{
die('missing option ' . $option);
}
}
if (count($argv) < 2)
{
die('error');
}
$args["col1"] = $argv[count($argv) - 2];
$args["col2"] = $argv[count($argv) - 1];
putenv("DB_CONNECTION=" . $args["engine"]);
putenv("DB_HOST=" . $args["hostname"]);
putenv("DB_PORT=" . $args["port"]);
putenv("DB_DATABASE=" . $args["database"]);
putenv("DB_USERNAME=" . $args["username"]);
putenv("DB_PASSWORD=" . $args["password"]);
ColumnChanger::swap($args["table"], $args["col1"], $args["col2"]);
}
Η κλήση στη γραμμή εντολών είναι αυτονόητη:
php ColumnChanger.php -e pgsql -h 127.0.0.1 -P 5432 -u username -p password -d database -t table col1 col2 php ColumnChanger.php -e mysql -h 127.0.0.1 -P 3306 -u username -p password -d database -t table col1 col2
Η ενσωμάτωση στο Laravel 5 γίνεται επίσης γρήγορα, απλά αντιγράφοντας το ColumnChanger.php στο φάκελο app / Helpers. Στη συνέχεια, μπορείτε να ανταλλάξετε στήλες απευθείας σε μετεγκαταστάσεις:
<?php
use Illuminate\Database\Schema\Blueprint;
use Illuminate\Database\Migrations\Migration;
class SwitchColumns extends Migration
{
/**
* Run the migrations.
*
* @return void
*/
public function up()
{
App\Helpers\ColumnChanger::swap("users","email","password");
}
/**
* Reverse the migrations.
*
* @return void
*/
public function down()
{
App\Helpers\ColumnChanger::swap("users","password","email");
}
}