Defining Macro Parameter

All datavault4dbt front-end macros have many parameters to configure the generated SQL code. These parameters can be defined in various ways, this page focuses on the most efficient ways.

Since datavault4dbt version 1.9, parameters can be directly inputted as the yaml_metadata, allowing multiple parameters to be set in one go.

An example Hub which uses this style of parameter setting looks like this:

{{ config(materialized='incremental') }}

{%- set yaml_metadata -%}
hashkey: 'hk_account_h'
business_keys: 
    - account_key
    - account_number
source_models: stage_account
{%- endset -%}

{{ datavault4dbt.hub(yaml_metadata=yaml_metadata) }}

The classic way of setting parameters in datavault4dbt already included yaml_metadata, but it was turned into individual parameters first, before passing them to the macro. The example from above would look like this with individually set parameters:

{{ config(materialized='incremental') }}

{%- set yaml_metadata -%}
hashkey: 'hk_account_h'
business_keys: 
    - account_key
    - account_number
source_models: stage_account
{%- endset -%}

{%- set metadata_dict = fromyaml(yaml_metadata) -%}

{{ datavault4dbt.hub(hashkey=metadata_dict.get('hashkey'),
                    business_keys=metadata_dict.get('business_keys'),
                    source_models=metadata_dict.get('source_models')
                    ) }}

Notice that this model is already a bit longer than the one which directly passes yaml_metadata!

All front-end macros are designed to work with both approaches, and to allow a combination of both ways of passing parameters.
We strongly recommend picking one style of passing parameters. Best, choose one for all your models, but at least don’t mix both styles in one model. You might encounter unexpected behavior.

A (bad) example of combining both styles would look like this:

{{ config(materialized='incremental') }}

{%- set yaml_metadata -%}
hashkey: 'hk_account_h'
business_keys: 
    - account_key
    - account_number
{%- endset -%}

{{ datavault4dbt.hub(yaml_metadata=yaml_metadata,
                    source_models=stage_account
                    ) }}

This example would not cause any unexpected behavior.

If a parameter is passed in both ways, individually and in the yaml_metadata, like in this example:

{{ config(materialized='incremental') }}

{%- set yaml_metadata -%}
hashkey: 'hk_account_h'
business_keys: 
    - account_key
    - account_number
source_models: stage_account
{%- endset -%}

{{ datavault4dbt.hub(yaml_metadata=yaml_metadata,
                    source_models=stage_customer
                    ) }}

the individual parameter is ignored! This hub will be loaded from stage_account, as defined in the yaml_metadata.