Hello @Rohit_hk ,

Below are the answers to your questions:

• Is this the expected behaviour (schemaHints only accepts an inline string and not a file path)?

Ans:

Yes, cloudFiles.schemaHints is defined as a plain String option, and we can only pass  DDL strings, not paths. There is no support for interpreting its value as a path to a JSON file .Doc :https://docs.databricks.com/aws/en/ingestion/cloud-object-storage/auto-loader/options

• Is there any supported way in DLT SQL to:

  • load a schema definition from a JSON file, and

  • feed it into cloudFiles / schemaHints (or another option) without hardcoding the full “col dtype, col2 dtype…” string in the SQL?

Ans:

Not directly. In a pure SQL DLT (Lakeflow Declarative Pipelines) notebook:

• You cannot read an arbitrary JSON file from DBFS/S3 and inject its contents into cloud_files or schemaHints at runtime.
• The options map in cloud_files/read_files must be literals or parameter expansions, not the result of reading a file.

However, DLT / Lakeflow pipelines support parameters whose values are injected into your SQL as strings Doc: https://docs.databricks.com/aws/en/ldp/parameters

You can:

1. Put this in your pipeline configuration (UI/JSON):

2. Reference it in your SQL notebook:

CREATE OR REFRESH STREAMING LIVE TABLE bronze_my_table AS
SELECT *
FROM STREAM cloud_files(
  's3://my-bucket/path',
  'parquet',
  map(
    'cloudFiles.schemaHints', '${myschema.my_table_hints}',
    'cloudFiles.schemaLocation', 'dbfs:/schemas/autoloader/my_table'
  )
);