Re: ArrowNotImplementedError: No cast implemented from decimal(2,2) to decimal(12,2)

[Дима Фомин]

Digging this I just found that this code breaks my Python Kernel :(

 

import sqlalchemy as sq

import pyarrow as pa

 

aaa, bbb = sq.sql.sqltypes.decimal.Decimal(123.234), sq.sql.sqltypes.decimal.Decimal(123.234)

ddd = [aaa, bbb]

pa.array(ddd)

 

So seems pyarrow.array is limited with types of array elements, doesnt'it?

 

WBR,

Dima Fomin

 

24.10.2019, 15:47, "Dima Fomin" <dat...@yandex.ru>:

Hello!

First of all thank you very much for your efforts on Apache Arrow! This looks very useful and prominent tech to be able use it in self-BI area.

 

I faced such issues - get Subj Error

ArrowNotImplementedError: No cast implemented from decimal(2,2) to decimal(12,2)

when trying to pyarrow.Table.from_batches array of values defined in schema as pyarrow.decimal128(12,2).

 

Which values are in fact column of sqlAlchemy.sql.sqltypes.DECIMAL()="DECIMAL(precision=12,scale=2)" values, which I map in schema like this pyarrow.decimal128(12,2).

 

What could be a reason of issue?

Could it be that somehow declared decimal type of data is reduced to minimum value which met in data? :/

 

With best regards,

Dima Fomin