Doctrine\DBAL\Platforms\MySqlPlatform::getAlterTableSQL PHP Method

    public function getAlterTableSQL(TableDiff $diff)
    {
        $columnSql = array();
        $queryParts = array();
        if ($diff->newName !== false) {
            $queryParts[] = 'RENAME TO ' . $diff->getNewName()->getQuotedName($this);
        }
        foreach ($diff->addedColumns as $column) {
            if ($this->onSchemaAlterTableAddColumn($column, $diff, $columnSql)) {
                continue;
            }
            $columnArray = $column->toArray();
            $columnArray['comment'] = $this->getColumnComment($column);
            $queryParts[] = 'ADD ' . $this->getColumnDeclarationSQL($column->getQuotedName($this), $columnArray);
        }
        foreach ($diff->removedColumns as $column) {
            if ($this->onSchemaAlterTableRemoveColumn($column, $diff, $columnSql)) {
                continue;
            }
            $queryParts[] = 'DROP ' . $column->getQuotedName($this);
        }
        foreach ($diff->changedColumns as $columnDiff) {
            if ($this->onSchemaAlterTableChangeColumn($columnDiff, $diff, $columnSql)) {
                continue;
            }
            /* @var $columnDiff \Doctrine\DBAL\Schema\ColumnDiff */
            $column = $columnDiff->column;
            $columnArray = $column->toArray();
            // Don't propagate default value changes for unsupported column types.
            if ($columnDiff->hasChanged('default') && count($columnDiff->changedProperties) === 1 && ($columnArray['type'] instanceof TextType || $columnArray['type'] instanceof BlobType)) {
                continue;
            }
            $columnArray['comment'] = $this->getColumnComment($column);
            $queryParts[] = 'CHANGE ' . $columnDiff->getOldColumnName()->getQuotedName($this) . ' ' . $this->getColumnDeclarationSQL($column->getQuotedName($this), $columnArray);
        }
        foreach ($diff->renamedColumns as $oldColumnName => $column) {
            if ($this->onSchemaAlterTableRenameColumn($oldColumnName, $column, $diff, $columnSql)) {
                continue;
            }
            $oldColumnName = new Identifier($oldColumnName);
            $columnArray = $column->toArray();
            $columnArray['comment'] = $this->getColumnComment($column);
            $queryParts[] = 'CHANGE ' . $oldColumnName->getQuotedName($this) . ' ' . $this->getColumnDeclarationSQL($column->getQuotedName($this), $columnArray);
        }
        if (isset($diff->addedIndexes['primary'])) {
            $keyColumns = array_unique(array_values($diff->addedIndexes['primary']->getColumns()));
            $queryParts[] = 'ADD PRIMARY KEY (' . implode(', ', $keyColumns) . ')';
            unset($diff->addedIndexes['primary']);
        }
        $sql = array();
        $tableSql = array();
        if (!$this->onSchemaAlterTable($diff, $tableSql)) {
            if (count($queryParts) > 0) {
                $sql[] = 'ALTER TABLE ' . $diff->getName($this)->getQuotedName($this) . ' ' . implode(", ", $queryParts);
            }
            $sql = array_merge($this->getPreAlterTableIndexForeignKeySQL($diff), $sql, $this->getPostAlterTableIndexForeignKeySQL($diff));
        }
        return array_merge($sql, $tableSql, $columnSql);
    }