dosubot[bot] commented on issue #34718: URL: https://github.com/apache/superset/issues/34718#issuecomment-3192059699
<!-- Answer --> The difference comes from how Superset extracts column type metadata for each dataset type. For physical datasets (direct tables/views), Superset uses SQLAlchemy's inspector to fetch column types straight from the database schema, which is usually explicit and reliable. For virtual datasets (defined by a SQL query), Superset runs your query with a limit (often 1 row) and tries to infer column types from the result set using the database driver's cursor description. This process can be less precise or even ambiguous, especially for types like float/double, because not all drivers provide detailed type info for query results. As a result, the same column might be recognized as numeric (with the # icon) in a physical dataset but not in a virtual one, even if the underlying data is identical. All chart controls and UI icons depend on this metadata pipeline, so these discrepancies are expected in some casesâespecially with edge-case types and certain drivers. You can see this logic in the code for [SqlaTable.external_metadata](https://github.com/apache/superset/blob/829e4d92d91ceae4b43b1ed3b063ffe45377799c/superset/connectors/sqla/models.py) and the utility functions for [fetching physical vs virtual metadata](https://github.com/apache/superset/blob/829e4d92d91ceae4b43b1ed3b063ffe45377799c/superset/connectors/sqla/utils.py). <!-- Dosu Comment Footer --> *To reply, just mention [@dosu](https://go.dosu.dev/dosubot).* --- <sup>How did I do? [Good](https://app.dosu.dev/response-feedback/7b0f89c4-f69b-44c9-a446-a0fee0f73fb3?feedback_type=great_response) | [Irrelevant](https://app.dosu.dev/response-feedback/7b0f89c4-f69b-44c9-a446-a0fee0f73fb3?feedback_type=irrelevant_answer) | [Incorrect](https://app.dosu.dev/response-feedback/7b0f89c4-f69b-44c9-a446-a0fee0f73fb3?feedback_type=incorrect_sources) | [Verbose](https://app.dosu.dev/response-feedback/7b0f89c4-f69b-44c9-a446-a0fee0f73fb3?feedback_type=too_verbose) | [Hallucination](https://app.dosu.dev/response-feedback/7b0f89c4-f69b-44c9-a446-a0fee0f73fb3?feedback_type=hallucination) | [Report đ](https://app.dosu.dev/response-feedback/7b0f89c4-f69b-44c9-a446-a0fee0f73fb3?feedback_type=bug_report) | [Other](https://app.dosu.dev/response-feedback/7b0f89c4-f69b-44c9-a446-a0fee0f73fb3?feedback_type=other)</sup> [](https://app.dosu.dev/a28d3c7e-a9d3-459e-9fb6-3a6f9ff4f357/ask?utm_source=githu b) [](https://go.dosu.dev/discord-bot) [](https://twitter.com/intent/tweet?text=%40dosu_ai%20helped%20me%20solve%20this%20issue!&url=https%3A//github.com/apache/superset/issues/34718) -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
