Doctrine2 Migration Using DBAL instead of $this->addSql

Question

So I've done a bunch of Doctrine2 migrations (https://github.com/doctrine/migrations) but I have a question for a new migration I'm trying to do.

I've been digging into the library a little and I see that $this->addSql() is used to build a list of SQL to execute and then it gets executed later.

I wanted to do something where I select some data, iterate over the rows, insert new data based on that, and then delete the data I selected. This lends itself to the DBAL library pretty easily, but I'm wondering, can I use the protected $connection in a migration safely? Or is that bad because it would execute statements before any of my $this->addSql() SQL gets executed? Also it seems like this would break the dry-run setting from what I've seen in the code. Has anyone had any experience with this type of migration? Are there any best practices?

The following is the migration I want to do, but I'm not confident that this is supported by Doctrine Migrations:

public function up(Schema $schema)
{
    // this up() migration is autogenerated, please modify it to your needs
    $this->abortIf($this->connection->getDatabasePlatform()->getName() != "mysql");

    $this->addSql("ALTER TABLE article_enclosures ADD is_scrape TINYINT(1) NOT NULL");
    $this->addSql("ALTER TABLE images DROP FOREIGN KEY FK_E01FBE6AA536AAC7");

    // now lets take all images with a scrape and convert the scrape to an enclosure
    // 
    // Select all images where not scrape_id is null (join on article_image_scrape)
    // for each image:
    //     insert into article_enclosures
    //     update image set enclosure_id = new ID
    //     delete from article_image_scrape where id...
    //
    // insert into article_enclosures select article_image_scrapes...

    $sql = "SELECT i.id img_id, e.* FROM images i JOIN article_image_scrapes e ON i.scrape_id = e.id";
    $stmt = $this->connection->prepare($sql);
    $stmt->execute();
    $scrapesToDelete = array();
    while ($row = $stmt->fetch()) {
        $scrapeArticle = $row['article_id'];
        $scrapeOldId = $row['id'];
        $scrapeUrl = $row['url'];
        $scrapeExtension = $row['extension'];
        $scrapeUrlHash = $row['url_hash'];
        $imageId = $row['image_id'];

        $this->connection->insert('article_enclosures', array(
            'url' => $scrapeUrl,
            'extension' => $scrapeExtension,
            'url_hash' => $scrapeUrlHash
        ));

        $scrapeNewId = $this->connection->lastInsertId();

        $this->connection->update('images', array(
            'enclosure_id' => $scrapeNewId,
            'scrape_id' => null
        ), array(
            'id' => $imageId
        ));

        $scrapesToDelete[] = $scrapeOldId;
    }

    foreach ($scrapesToDelete as $id) {
        $this->connection->delete('article_image_scrapes', array('id' => $id));
    }

    $this->addSql("INSERT INTO article_scrapes (article_id, url, extension, url_hash) "
            ."SELECT s.id, s.url, s.extension, s.url_hash"
            ."FROM article_image_scrapes s");

    $this->addSql("DROP INDEX IDX_E01FBE6AA536AAC7 ON images");
    $this->addSql("ALTER TABLE images DROP scrape_id, CHANGE enclosure_id enclosure_id INT NOT NULL");
}

Answer 1

You can use the $connection like this

$result = $this->connection->fetchAssoc('SELECT id, name FROM table1 WHERE id = 1');
$this->abortIf(!$result, 'row with id not found');
$this->abortIf($result['name'] != 'jo', 'id 1 is not jo');
// etc..

You should only read the database and not use the connection to make update/delete so it won't break the dry-run option.

In your example, you should do two migrations. The first will do the two alter table. The second will do the "images with a scrape and convert the scrape to an enclosure" routine. Using multiple migration is easier to revert them if something goes wrong.