AS 400 Data Being Interpreted As Unicode Strings (DT_WSTR) Datatype

I am building a data warehouse. Some of the data comes from an AS 400 EPR system. I used the OLEDB connector when first pulling the data into SQL Server doing simple import data from table option. That worked great for getting the initial data load into SQL Server and creating the base SQL Server tables although it was excruciatingly slow (that was probably due to the transport from the AS 400).

Now, I need to get new records that are added to the AS400 side of things on a daily basis. For that, I was trying to use the OLEDB AS400 connector. However, I found that the OLEDB connector wouldn't work when I was trying to specify an SQL Statement for what to get; i.e., a simple query like Select * from TWLDAT.STKT where BYSDAT >= '2005-01-27' would simply not work. Found articles here explaining that it is probably a problem on the AS400 side of things and where people recommended using an ADO ODBC data reader source for this type of thing. So, I'm trying to implement that. However, I have a huge problem with it.

The original tables that got created were mapped to use NVARCHAR fields for character data. When the ADO ODBC data reader source accesses the AS400 data, it insists on interpreting the string type fields as being unicode strings and giving it a data type of DT_WSTR when what I need it to have is a plain old DT_STR data type. When the strings are interpreted as unicode strings, they cannot be converted in a way that allows the NVARCHAR fields to be filled with the data. The exact error message I get for all the fields that should wind up being nvarchar fields is as follows:

Column "BYStOK" cannot convert between unicode and non-unicode string data types.

Okay, so I try to change the data types in the ADO ODBC data reader to be plain DT_STR data types and I cannot do so.

Does anyone have any idea why the ADO ODBC data reader source insists on interpreting the string data coming from the AS 400 as unicode string data or why it refuses to allow that to be changed to DT_STR data type?

Thanks in advance for any info. By the way, if there is a better way than the ADO ODBC data source to get at this data when I need to specify an SQL command, I would love to hear about it. Not wild about using ODBC in the OLEDB age.



Steve Wells