Inserts or updates multiple items in a collection.
The Bulk Save Data Items endpoint inserts or updates each item provided, depending on whether it already exists in the collection. For each item:
If you don't provide an ID, a new item is created.
If you provide an ID that doesn't exist in the collection, a new item is created with that ID.
If an item with the ID you provide already exists in the collection, that item is updated. When an item is updated, its data._updatedDate field is changed to the current date and time.
Note: When you provide an item with an ID that already exists in the collection, the item you provide completely replaces the existing item with that ID. This means that all of the item's previous fields and values are lost.
You can only call this method when authenticated as a Wix app or Wix user identity.