Question

I’m writing a tool the retrieves data from an Oracle database. The majority of the fields are VARCHAR2, but there’s one particular field I want to retrieve that is a CLOB. I’m trying to convert the text in this CLOB to a string that I can then run a regex against it to isolate a certain bit of information and then display that information in the program’s console. Unfortunately, I can’t seem to figure out how to convert this CLOB into a usable string.

I’ve tried a lot of different things, but what I’ve got at the moment is:

---

    With OraDynaset
        If .RecordCount > 0 Then
            .MoveFirst()
            While (Not .EOF Or .BOF)
                m_StrThis = .Fields("This").Value
                clobSupportProcs = .Fields("That").Value
                m_strThat = (clobSupportProcs).ToString
                .MoveNext()
            End While
        End If
    End With

---

The field “This” works fine, as it’s not a CLOB. The field “That” is the troublemaker. I’ve read in other posts that there’s a way to stream this in chunks into something usable, but I’ve yet to see a clear example of how this is done.

I’d appreciate any CONSTRUCTIVE comments or help. I understand that using a CLOB wasn’t necessary to begin with — this database is over 10 years old however. I have no control over that. I understand that I’m connecting to the database in a less than elegant way. I don’t care about that. I just need these two little bits of information. I’m not a pro, just a guy trying to write a tool that will make his life easier. Any help is much appreciated. Unhelpful comments are not.

Thanks!

Answer 1

I was finally able to figure this out by playing with the possible properties and methods.

The solution is:

Dim clobSupportProcs As OracleInProcServer._IOraClob
Dim clobSize As Integer
Dim clobOut As String

With OraDynaset
        If .RecordCount > 0 Then
            .MoveFirst()
            While (Not .EOF Or .BOF)
                m_StrThis = .Fields("THIS").Value
                clobSupportProcs = .Fields("THAT").Value
                clobSize = clobSupportProcs.size

                If clobSize > 0 Then
                    clobSupportProcs.Read(clobOut)
                    m_strThat= clobOut
                Else
                    m_strThat= "None"
                End If

                .MoveNext()
            End While
        End If
    End With

So basically, you read the clob to a string (clobOut).