[C++/Python] Validate scale and precision of decimal128 type

[asfimport]

Do We have a specification for it?
Currently I can create pa.decimal128(-2147483648, 2147483647), which seems wrong.

References:

• https://docs.microsoft.com/en-us/sql/t-sql/data-types/precision-scale-and-length-transact-sql?view=sql-server-2017
• https://docs.oracle.com/cd/B28359_01/server.111/b28318/datatype.htm#CNCPT1832

Reporter: Krisztian Szucs / @kszucs
Assignee: Antoine Pitrou / @pitrou

Related issues:

• [Python] pa.decimal128 should validate inputs (is superceded by)

_{Note: This issue was originally created as ARROW-3904. Please see the migration documentation for further details.}

[asfimport]

Wes McKinney / @wesm:
In PostgreSQL it seems to be configurable

https://www.postgresql.org/docs/10/datatype-numeric.html#DATATYPE-NUMERIC-DECIMAL

Parquet supports precision 1 through 38 (https://github.com/apache/parquet-format/blob/master/LogicalTypes.md#decimal). It seems scale is limited to be between 0 and 38. So that seems like a reasonable constraint for now

[asfimport]

Antoine Pitrou / @pitrou:
This was fixed in ARROW-4563.