Shopify Update Strategy

To create a transaction in Shopify, set the desired fields, but do not specify a value against the ‘id’ field. If a field is mapped to an id field and the field is empty, the field will be populated with the id assigned by Shopify to the field.

To update a record in Shopify specify the record’s valid ‘id’ field. Some import types, such as updating an existing product's default variant require that both the id and variant_id are specified.

Similarly, to associate a new transaction with an existing transaction i.e. a fulfillment with an order, typically you specify the original transaction’s id, and/or the line id.