Interŝanĝi kolumnojn en PostgreSQL

Interŝanĝi SQL-tabelajn kolumnojn estas parto de la norma repertuaro kun MySQL - ĉi tio (ankoraŭ) ne estas subtenata per PostgreSQL. Kvankam la oficiala vikio dediĉas sian propran artikolon al la problemo, ĝi ne montras ian praktikan solvon, kiu ankaŭ subtenas vidpunktojn, indeksojn kaj ekigilojn. La sekva klaso plenumas ĉi tiun taskon (kaj por MySQL kaj PostgreSQL) ĉu sur la komandlinio - ĉu rekte rekte en 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"]);
	
}

La alvoko sur la komandlinio estas memkomprenebla:

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

La integriĝo en Laravel 5 ankaŭ fariĝas rapide simple kopiante ColumnChanger.php en la dosierujo app / Helpers. Vi povas tiam interŝanĝi kolumnojn rekte en migradoj:

<?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");
    }
}
Reen