Oracle 编号映射 (ODP.NET)

Question

According to the Oracle documentation, a NUMBER(5,0) column could hold Int16 and partially Int32 values. I'm developing an application (using ODP.NET ) without the Entity Framework (EF), and can't define custom mappings (edmMappings) in an App.Config file. ODP.NET doesn't support edmMappings in non-EF applications (at least they are ignored).

Tested edmMappings:

• <add NETType="int16" MinPrecision="4" MaxPrecision="5" DBType="Number" />
• <add name="int16" precision="4" /> (note; next one is int32 which is using precision 9)
• <add name="int16" value="edmmapping number(4,0)" /> (note; next one is int32 which is using precision 9)

This is causing 'issues' in the application, because it expects the Int16 datatype when executing a select query, which contains the NUMBER(5,0) column.

At this moment, I can only think of the next (not prefered) solutions:

1. Change the NUMBER(5,0) column to NUMBER(4,0) .
2. Cast the cell value (of the NUMBER(5,0) ) to an Int32 (instead of the expected Int16 type).

---

Is it somehow possible to (always) map a NUMBER(5,0) column to an Int16 (.NET type)?

(Perhaps I'm not aware of a certain setting and/or field of the OracleConnection, OracleDataAdapter or OracleDataReader class).

Answer 1

Absolutely not possible, for a trivial reason: number(5,0) can hold any integer between -99999 and 99999, while int16 can only hold 65536 distinct values. Not enough room for any one-to-one mapping.

Note that this is not a limitation of any language - it is a logical impossibility.