comphead commented on code in PR #15329: URL: https://github.com/apache/datafusion/pull/15329#discussion_r2007928627
########## docs/source/library-user-guide/working-with-exprs.md: ########## @@ -50,6 +50,25 @@ As another example, the SQL expression `a + b * c` would be represented as an `E As the writer of a library, you can use `Expr`s to represent computations that you want to perform. This guide will walk you through how to make your own scalar UDF as an `Expr` and how to rewrite `Expr`s to inline the simple UDF. +## Arrow Schema and DataFusion DFSchema + +Schema and DFSchema are both exist in datafusion because `Schema` provides a lightweight structure for defining data, and `DFSchema` extends it with extra information. This makes the engine could handle both simple data definitions and complex query scenarios efficiently. Review Comment: ```suggestion Apache Arrow `Schema` provides a lightweight structure for defining data, and Apache Datafusion`DFSchema` extends it with extra information such as column qualifiers and functional dependencies. Column qualifiers are multi part path to the table e.g table, schema, catalog. Functional Dependency is the relationship between attributes(characteristics) of a table related to each other. ``` -- 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: github-unsubscr...@datafusion.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org --------------------------------------------------------------------- To unsubscribe, e-mail: github-unsubscr...@datafusion.apache.org For additional commands, e-mail: github-h...@datafusion.apache.org
