Problems obtaining column length data from ADO.Net

Norman Lastovica · *nix forums beginner Joined: 22 Jul 2005 Posts: 30

you best bet here would probably to start with
calling Rdb support directly.

Bob Jarvis wrote:

Bob Jarvis · *nix forums beginner Joined: 25 Jan 2006 Posts: 2

We have a .NET web app which has been working well using a 2.0 version
of the Oracle Rdb ODBC driver. Management has decreed that we must use
the latest 3.0 Oracle Rdb ODBC driver (v3.01.00.02) on a new server.
Here's a code example of what we're doing:

Private pCnn As New OdbcConnection
Dim Ds As DataSet = New DataSet
Dim Da As New OdbcDataAdapter("SELECT * FROM " & TableName, pCnn)

Da.FillSchema(Ds, SchemaType.Mapped, TableName)

Under the 2.0 driver we find that after the FillSchema call all
attributes for columns in the DataSet are properly filled in and we go
on our merry way. When using the 3.0 driver, however, we find that
after FillSchema is called the MaxLength property on all columns in the
DataSet are not set (all are zeroed out), and thus when we try to
assign string values to various columns we get an error saying
something like "Cannot assign XXXXXXXXXXXX to column COLUMN_NAME
because the new value exceeds the maximum length". We thought about
setting the MaxLength property ourselves but found that it is not a
settable property.

We've traced ODBC activity and have found a couple of failures when
ADO.Net is calling SQLColAttribute for attributes 1211 and 1212. I've
found no documentation for what these attribute descriptor numbers
might be, and the values for SQL_DESC_* in SQL.H don't seem to be in
that range.

My questions:
1. Has anyone else encountered this problem? (Surely we're not the
first!)
2. Workaround? Fix?
3. Is this an MS problem or an Oracle problem?
4. Is there a newer version of the Oracle Rdb ODBC driver?

Any help or advice appreciated.

Google