tustvold commented on code in PR #50839: URL: https://github.com/apache/arrow/pull/50839#discussion_r4040462584
########## docs/source/format/Columnar.rst: ########## @@ -864,6 +864,12 @@ A union is defined by an ordered sequence of types; each slot in the union can have a value chosen from these types. The types are named like a struct's fields, and the names are part of the type metadata. +Each child type in a union has a type id (an 8-bit signed integer) +that identifies it in the types buffer. By default, these type ids +correspond directly to the child array indices (0, 1, ...), but an optional +``typeIds`` metadata array can provide an explicit mapping from child array Review Comment: It isn't clear from this how they actually do this, I think an example would make it clear. -- 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]
