I believe it would be something like (pseudocode since the last time I touched
C♯ was, 2009?)
List<Field> TABLE_SCHEMA = new[]{
...,
new Field("table_columns", new ListType(new StructType(COLUMN_SCHEMA)),
...,
};
i.e. COLUMN_SCHEMA gets passed as the fields of a StructType itself instead of
the field containing the StructType. (Which saves you some typing too since you
don't have to explicitly name the list child field.)
On Thu, Mar 9, 2023, at 16:20, David Coe wrote:
> I am investigating whether ADBC can be a replacement for ODBC in
> certain scenarios and help with more efficient copying.
>
> For example, in
> https://github.com/apache/arrow-adbc/blob/923e0408fe5a32cc6501b997fafa8316ace25fe0/java/core/src/main/java/org/apache/arrow/adbc/core/StandardSchemas.java#L116
>
> it wants COLUMN_SCHEMA and CONSTRAINT_SCHEMA as children but there's
> not an obvious way to add those children to the respected fields.
>
> -----Original Message-----
> From: David Li <lidav...@apache.org>
> Sent: Thursday, March 9, 2023 3:37 PM
> To: dev@arrow.apache.org
> Subject: [EXTERNAL] Re: Field class in Java vs C#
>
> [You don't often get email from lidav...@apache.org. Learn why this is
> important at https://aka.ms/LearnAboutSenderIdentification ]
>
> I'd be very interested if I can help in any way with porting ADBC to
> more languages, and learning more about use cases/what functionality is
> useful (e.g. are you looking to have a full driver/client ecosystem in
> C♯, or are you interested in being able to leverage drivers written in
> C/C++/Go?)
>
> From a quick look, C♯ follows C++, Python, etc. in putting child fields
> as part of the nested type, rather than as part of the field itself. I
> can't say why precisely one implementation chose one design or another,
> but Java basically follows the IPC format exactly in this regard (and
> others, e.g. it has a parameterized Int type rather than Int32, Int64,
> UInt32, etc.), while the other languages model it at a higher level
> (because only some types can have children).
>
> What specifically is difficult with the how the APIs are structured?
>
> On Thu, Mar 9, 2023, at 15:19, David Coe wrote:
>> I am interested in the difference between how a Field is structured in
>> Java (with children) and in C# (no children) and why that's the case.
>>
>> I am looking to port apache/arrow-adbc: Apache arrow
>> (github.com)<https://nam06.safelinks.protection.outlook.com/?url=https
>> %3A%2F%2Fgithub.com%2Fapache%2Farrow-adbc&data=05%7C01%7CDavid.Coe%40microsoft.com%7Cedcb6c5cec5f41e653ac08db20de28e7%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C638139910769892299%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=6bc%2BVEFR2syJFe%2FwzSTHwSMeLka8U48r9mypFbspkIQ%3D&reserved=0>
>> to C# but the concept of children is making it a little hairy.
>>
>>
>> * David
