Craft\m160515_005002_Neo_UpdateBlockStructure::safeUp PHP Method

    public function safeUp()
    {
        // Create the craft_neoblockstructures table
        $this->createTable('neoblockstructures', ['structureId' => ['column' => 'integer', 'required' => true], 'ownerId' => ['column' => 'integer', 'required' => true], 'fieldId' => ['column' => 'integer', 'required' => true]], null, true);
        // Add indexes to craft_neoblockstructures
        $this->createIndex('neoblockstructures', 'structureId', false);
        $this->createIndex('neoblockstructures', 'ownerId', false);
        $this->createIndex('neoblockstructures', 'fieldId', false);
        // Add foreign keys to craft_neoblockstructures
        $this->addForeignKey('neoblockstructures', 'structureId', 'structures', 'id', 'CASCADE', null);
        $this->addForeignKey('neoblockstructures', 'ownerId', 'elements', 'id', 'CASCADE', null);
        $this->addForeignKey('neoblockstructures', 'fieldId', 'fields', 'id', 'CASCADE', null);
        // Migrate existing fields
        $structures = [];
        $parentStacks = [];
        $rawBlocks = craft()->db->createCommand()->select('*')->from('neoblocks')->order('sortOrder asc')->queryAll();
        if ($rawBlocks) {
            foreach ($rawBlocks as $rawBlock) {
                $block = new Neo_BlockModel_1_0_2();
                $block->id = intval($rawBlock['id']);
                $block->ownerId = intval($rawBlock['ownerId']);
                $block->fieldId = intval($rawBlock['fieldId']);
                $block->typeId = intval($rawBlock['typeId']);
                $block->level = intval($rawBlock['level']);
                $key = $block->ownerId . ':' . $block->fieldId;
                if (!isset($structures[$key])) {
                    $structures[$key] = new StructureModel();
                    $parentStacks[$key] = [];
                    craft()->structures->saveStructure($structures[$key]);
                    $this->insert('neoblockstructures', ['structureId' => $structures[$key]->id, 'ownerId' => $block->ownerId, 'fieldId' => $block->fieldId]);
                }
                $structure = $structures[$key];
                $parentStack = $parentStacks[$key];
                while (!empty($parentStack) && $block->level <= $parentStack[count($parentStack) - 1]->level) {
                    array_pop($parentStack);
                }
                if (empty($parentStack)) {
                    craft()->structures->appendToRoot($structure->id, $block);
                } else {
                    $parentBlock = $parentStack[count($parentStack) - 1];
                    craft()->structures->append($structure->id, $block, $parentBlock);
                }
                array_push($parentStack, $block);
                $structures[$key] = $structure;
                $parentStacks[$key] = $parentStack;
            }
        }
        // Remove columns from craft_neoblocks
        $this->dropColumn('neoblocks', 'sortOrder');
        $this->dropColumn('neoblocks', 'level');
        return true;
    }