https://dagster.io/ logo
#ask-ai
Title
# ask-ai
p

Pierre Cadman

02/27/2024, 4:14 PM
How can I make a static partition depend on a specific upstream asset?
s

Scout

02/27/2024, 4:14 PM
To define dependencies between a static partition and a specific upstream asset, you can use a
PartitionMapping
to explicitly map the relationship between the partitions of the upstream and downstream assets. The documentation provides several types of
PartitionMapping
that you can use depending on your specific use case: 1. StaticPartitionMapping: This allows you to define an explicit correspondence between two
StaticPartitionsDefinitions
. You can specify a single or multi-valued correspondence from upstream keys to downstream keys. 2. SpecificPartitionsPartitionMapping: This mapping is used to map to a specific subset of partitions in the upstream asset. Here's an example from the documentation using `SpecificPartitionsPartitionMapping`:
Copy code
python from dagster import SpecificPartitionsPartitionMapping, StaticPartitionsDefinition, asset  @asset(partitions_def=StaticPartitionsDefinition(["a", "b", "c"])) def upstream():     ...  @asset(     ins={         "upstream": AssetIn(partition_mapping=SpecificPartitionsPartitionMapping(["a"]))     } ) def a_downstream(upstream):     ...
In this example, the downstream asset
a_downstream
depends on the "a" partition of the upstream asset
upstream
. Remember to choose the appropriate
PartitionMapping
based on whether you want a one-to-one mapping, a one-to-many mapping, or a mapping to a specific subset of partitions. The
PartitionMapping
you choose will define how the downstream asset's partitions relate to the upstream asset's partitions.
p

Pierre Cadman

02/27/2024, 4:18 PM
Can I convert an asset to a partition