"No data exists for the row/column." executing OLEDB Oracle OleDbDataReader - vb.net

Question

I know this is very basic, and I've done this hundreds of times. But, for some strange reason I am executing this command on a database, and it fails when it tries to read a column from the result. If I execute this statement in SQL Plus logged in as the same credentials, the row (table has 1 row) is selected just fine. Any ideas what I am doing wrong? I tried accessing the columns by name, by index, and indeed any column - all of them give no data. I tried without the .NextResult() (just in case), same exception.
'...
' Determine if this database is Multisite enabled
Dim multisiteCmd As OleDbCommand = DbConnection.CreateCommand
multisiteCmd.CommandText = "SELECT * FROM TDM_DB_VERSION;"
Dim dbVersionReader As OleDbDataReader = multisiteCmd.ExecuteReader()
If dbVersionReader.HasRows Then
dbVersionReader.NextResult()
'If a ReplicaID was generated for the Database ID, then this is part of a
'multisite implementation
'Dim dbRepID As String = dbVersionReader("DB_REPLICID")
Dim dbRepID As String = dbVersionReader(9)
PluginSettings.UseMultisite = False
If Not dbRepID Is Nothing Then
If dbRepID.Length > 0 Then
PluginSettings.UseMultisite = True
PluginSettings.MultisiteReplicaId = dbRepID
End If
End If
End If
dbVersionReader.Close()
As you can see from these Immediate commands, the connection is open:
? DbConnection.Provider
"OraOLEDB.Oracle"
? DbConnection.State
Open {1}

Answer 1

NextResult() is for statements that have more than one result set. For example, if you had sent a command like this:
"SELECT * FROM TDM_DB_VERSION;SELECT * FROM dual;"
Note there are two queries in there. You can handle them both with a single call to the database and a single OleDbDataReader, and NextResult() is part of how you do that.
What you want instead is this:
Dim multisiteCmd As OleDbCommand = DbConnection.CreateCommand
multisiteCmd.CommandText = "SELECT * FROM TDM_DB_VERSION;"
Dim dbVersionReader As OleDbDataReader = multisiteCmd.ExecuteReader()
If dbVersionReader.Read() Then
'If a ReplicaID was generated for the Database ID, then this is part of a
'multisite implementation
'Dim dbRepID As String = dbVersionReader("DB_REPLICID")
Dim dbRepID As String = dbVersionReader(9)
PluginSettings.UseMultisite = False
If Not dbRepID Is Nothing Then ' Do you mean check for DbNull here? "Nothing" is not the same thing
If dbRepID.Length > 0 Then
PluginSettings.UseMultisite = True
PluginSettings.MultisiteReplicaId = dbRepID
End If
End If
End If
dbVersionReader.Close()