Origin Model

In AQL, when you apply transformations on a Table or a Field (like select or filter), it outputs a new Table or a Field object that still retains information about the first model that you used.

For example, in the AML layer you have defined a model called order_items, and then you apply some transformations to it:

Model order_items {
  dimension item_id {}
  dimension order_id
  dimension product_id {}
  dimension quantity {}
}

Model products {
  dimension id {}
  dimension price {}
}

Imagine that you use SQL to query these two models:

select
    oi.quantity * p.price as item_value
from order_items oi
left join products p on oi.product_id = p.id

After this SQL transformation, you will have a new table with only one column (item_value) and there is no information about order_items or products models.

with order_items_transformed as (
        select
            order_items.quantity * products.price as item_value
        from order_items
        left join products on order_items.product_id = products.id
    )

// Invalid
select
    order_items.order_id
from order_items_transformed

With AQL, the same transformation will also produce a new table with only a value column:

// Output a new virtual 'order_items_transformed' table
order_items | select(item_value: order_items.quantity * products.price)

However, the new table still retains the information about order_items. In this case, order_items is the origin model of the new order_items_transformed table. After the transformation, you can still access information of order_items:

order_items
| select(item_value: order_items.quantity * products.price)
| select(order_items.order_id, order_items.item_id, item_value)