I have a successful migration of content type A, B and C. In the migration of C, I have entity reference fields that get populated with the correct values coming from migration A and B.
My reference fields is a multi value node entity reference field. To prevent the values being over ridden from my previous migrations, I use the system of record method.
https://www.drupal.org/node/1117454 https://www.drupal.org/node/2550939
The example is very specific to a commerce migration.
// If "updating" a product, protect these fields.
// We know its updating if the product exists in the database with the sku.
// Migrate updates by deleting an entire entity and replacing with
// the new one. We circumvent the removal of the values of these
// fields by pulling them and overriding the defaults provided
// in the mapping.
// You could do the same with a nid id found with a title, or something similar.
// $row->migrate_map_sourceid1 is usually the entity id you're looking for,
// our example here uses a commerce_product and loads it with the provided sku
if ($product = commerce_product_load_by_sku($row->sku)) {
// Use the metatdata wrapper to pull values
$product_wrapper = entity_metadata_wrapper('commerce_product', $product);
// field_stock
// Some products have a NULL stock, lets keep the zero default if NULL
if ($product_wrapper->field_stock->value() !== NULL) {
$row->stock = $product_wrapper->field_stock->value();
} else { $row->stock = 0; }
// field_max
$row->max = $product_wrapper->field_max->value();
}
I am not sure how I would use my prepare row, current content types, their ids etc to remove the current values, update the new values, and then add the previous ones again? Or am I misunderstanding how this is suppose to work? Thanks in advance!
