Oracle OLE DB: Charset and FetchSize Configuration Issues

numensrl_it — Mon, 29 Dec 2025 12:21:51 GMT

Hi,

one of our data sources is an Oracle database. We created an OLE DB data connection to run SELECT queries; however, we encountered some issues:

When we use a simple connection string, for example:
OLEDB CONNECT TO [Provider=OraOLEDB.Oracle;Data Source=mydatasource;]
the connection works correctly and we do not experience any charset issues, but data extraction is very slow.
When we add the FetchSize parameter to improve data extraction performance, for example:
OLEDB CONNECT TO [Provider=OraOLEDB.Oracle;FetchSize=200000;Data Source=mydatasource;]
the connection becomes significantly faster, but we encounter charset issues and had to force to cast NCHAR fields to NUMBER: (CAST(Cd_Campo as Number(12)) as Cd_Campo
We attempted to explicitly force the charset in the OLE DB connection, for example:
OLEDB CONNECT TO [Provider=OraOLEDB.Oracle;FetchSize=200000;Extended Properties="CharacterSet=UTF8";Data Source=mydatasource;]
but this did not resolve the issue.

topic Oracle OLE DB: Charset and FetchSize Configuration Issues in App Development