klion26 commented on issue #6700: URL: https://github.com/apache/arrow-rs/issues/6700#issuecomment-3060670367
@alamb, I have some questions after conducting an analysis; I'm not sure if we need to make this change. Could you please help to confirm this? I can submit a PR if this change is needed. thanks. From the [Columnar.rst](https://github.com/apache/arrow/blob/main/docs/source/format/Columnar.rst#schema-message), it says that the flatbuffers type does not contain the metadata ``` The Field Flatbuffers type contains the metadata for a single array. This includes: The field's name The field's data type Whether the field is semantically nullable. While this has no bearing on the array's physical layout, many systems distinguish nullable and non-nullable fields and we want to allow them to preserve this metadata to enable faithful schema round trips. A collection of child Field values, for nested types A dictionary property indicating whether the field is dictionary-encoded or not. If it is, a dictionary "id" is assigned to allow matching a subsequent dictionary IPC message with the appropriate field. ``` But in [Schema.rst](https://github.com/apache/arrow/blob/main/format/Schema.fbs#L512), it says that the `Field` contains a user-defined metadata, ``` table Field { /// Name is not required (e.g., in a List) name: string; /// Whether or not this field can contain nulls. Should be true in general. nullable: bool; /// This is the type of the decoded value if the field is dictionary encoded. type: Type; /// Present only if the field is dictionary encoded. dictionary: DictionaryEncoding; /// children apply only to nested data types like Struct, List and Union. For /// primitive types children will have length 0. children: [ Field ]; /// User-defined metadata custom_metadata: [ KeyValue ]; } ``` -- 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...@arrow.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org
