# Where to put is\_incremental / how to structure incremental child/parent models

**URL:** <https://discourse.getdbt.com/t/where-to-put-is-incremental-how-to-structure-incremental-child-parent-models/8419>\
**Category:** Help\
**Tags:** incremental, snowflake\
**Created:** [May 24, 2023, 1:24pm UTC](https://discourse.getdbt.com/t/where-to-put-is-incremental-how-to-structure-incremental-child-parent-models/8419 "2023-05-24T13:24:49Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![george.jeffery](https://sea2.discourse-cdn.com/flex020/user_avatar/discourse.getdbt.com/george.jeffery/32/2456_2.png) [@george.jeffery](https://discourse.getdbt.com/u/george.jeffery)\
**Post date:** [May 24, 2023, 1:24pm UTC](https://discourse.getdbt.com/t/where-to-put-is-incremental-how-to-structure-incremental-child-parent-models/8419/1 "2023-05-24T13:24:49Z")

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Hi!

I’ve run into a bit of confusion about how best to structure a couple of models that use a few different sources, and how best I can make them incremental.

For context - we have 2 sources, one (_web\_old_) is no longer getting new information and the other (_web\_new_) is.

We have a _order\_completed_ table in both of them.

What I’ve done is set up a basic transformation model for both of them. Due to some difficulties with the raw data the transformation isn’t exactly the same, but the output is the same.

_base\_web\_old\_\_order\_completed_ / _base\_web\_new\_\_order\_completed_

I’ve then _union\_relations()_ them both in _base\_web\_combined\_\_order\_completed_ and done some window functions in _final()_ so I can count occurrences etc - this needs to happen here as there will be common user\_ids across both tables.

Now the question is - do I need to make _base\_web\_new\_\_order\_completed_ incremental, or do I just need to make _base\_web\_combined\_\_order\_completed_ incremental? My guess is that I’d want to make _base\_web\_new\_\_order\_completed_ so it’s not rebuilding every time the model runs, and I’d also want _base\_web\_combined\_\_order\_completed_ to be incremental.

For the combined model, do I want to add an _if\_incremental()_ block to both the _union\_relations()_ CTE as well as the final _select_ query?

Alternatively, am I doing this completely wrong and I don’t need the individual transformation models - so I should just add them all into one _combined_ model - but I don’t think I can use _union\_relations()_ on CTEs?

Thanks!