4 ms·

How aware is the library regarding existing structure, e.g foreign key relationships?

• cpimhoff 3y ago
  The library itself provides tools for declaring data tables, columns, metrics, and relationships, then performing transformations (eg. queries) on top of them. Reflecting an existing database isn't part of the library, but with the magic of "it's just Python" it's pretty easy to write a function that does so yourself: import hashquery as hq def reflect_db(url: str) -> list[hq.Model]: """ Given a connection string, returns a list of Hashquery models for all the physical tables in the database. """ models: list[hq.Model] = [] reflection = some_reflection_lib.reflect_db(url) for table in reflection.tables: models.append( hq.Model() .with_source(url, table.name, table.schema) .with_attributes(*table.column_names) ) # ...more logic for importing foreign keys or whatever else return models
• vndrewlee 3y ago
  Joining logic is defined in our data modeling layer, either from Hashboard (our BI tool) or can also be defined in Hashquery as well instead of replying on your database schema for fk relationships. We went this route since a lot of people are using dbt generated tables. https://hashquery.dev/docs/pattern_guides/joins/ https://hashquery.dev/docs/pattern_guides/joins/