Hi David Coe, As David Li pointed out, ADBC implementations can either be based purely within a language (C#-specific drivers that can only be used by C# programs) or use C API drivers written in other languages (C, C++, Go). For the latter, we won't be able to implement this until we finish implementing the C Data Interface [1] and C Stream Interface [2]. And for both approaches, I think we need to implement Union and Map types for GetInfo, which currently aren't implemented in Arrow C#.
Best, Will Jones [1] https://github.com/apache/arrow/issues/33856 [2] https://github.com/apache/arrow/issues/33857 On Thu, Mar 9, 2023 at 1:38 PM David Coe <david....@microsoft.com.invalid> wrote: > Yes, ok, I see the pattern now. Thanks you. > > -----Original Message----- > From: David Li <lidav...@apache.org> > Sent: Thursday, March 9, 2023 4:30 PM > To: dev@arrow.apache.org > Subject: Re: [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 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://nam06.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgith > > ub.com%2Fapache%2Farrow-adbc%2Fblob%2F923e0408fe5a32cc6501b997fafa8316 > > ace25fe0%2Fjava%2Fcore%2Fsrc%2Fmain%2Fjava%2Forg%2Fapache%2Farrow%2Fad > > bc%2Fcore%2FStandardSchemas.java%23L116&data=05%7C01%7CDavid.Coe%40mic > > rosoft.com%7C79f83852d98644220a2808db20e58966%7C72f988bf86f141af91ab2d > > 7cd011db47%7C1%7C0%7C638139942453273749%7CUnknown%7CTWFpbGZsb3d8eyJWIj > > oiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C > > %7C%7C&sdata=AHmBdvmzfH8vIabO8Z91HzqD%2BexwKNUn4McJQavldRM%3D&reserved > > =0 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=http > >> %3A%2F%2Fhttps%2F&data=05%7C01%7CDavid.Coe%40microsoft.com%7C79f83852 > >> d98644220a2808db20e58966%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0%7 > >> C638139942453273749%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQI > >> joiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=EDG87 > >> XRgoxsU9x0bQ4zi0HcyxRytJMb8p3RsXR6xuO8%3D&reserved=0 > >> %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 >
