I connect to an Access 2000 database, containing a table that has the

two fields CKey (type Text) and CValue (type Memo). The following code

generates an exception whenever the value for column CValue is an

empty string ('allow zero length' is set in mdb):





Dim cmd As New OleDbCommand()

cmd.Connection = TestConnection

cmd.CommandText = "INSERT INTO MyTable( CKey , CValue ) VALUES ( ?, ?

)"



Dim p1 As New OleDbParameter("@p1", OleDbType.VarWChar, 0,

ParameterDirection.Input, True, 0, 0, "CKey", DataRowVersion.Current,

"")

Dim p2 As New OleDbParameter("@p2", OleDbType.LongVarWChar, 0,

ParameterDirection.Input, False, 0, 0, "CValue",

DataRowVersion.Current, "")



p1.Value = Guid.NewGuid().ToString()

p2.Value = "" 'works if set to something else then empty string

cmd.Parameters.Add(p1)

cmd.Parameters.Add(p2)



TestConnection.Open()

cmd.ExecuteNonQuery()   ' exception raised

TestConnection.Close()





The exception message is our old friend:

"Multiple-step OLE DB operation generated errors. Check each OLE DB

status value, if available. No work was done."



The exception does not occur if I change the type of parameter 2 from

LongVarWChar to VarWChar. This is in particular enjoying, because the

OleDbCommandBuilder generates parameters of type LongVarWChar for Memo

fields.



Does anybody know why this happens? Does it matter if I use VarWChar

in place of LongVarWChar?



Thanks,

Godwin.





PS: I am using 'Visual Studio Enterprise Architect V2002'