Handling different datatypes (Text, Numbers, plus CLOB, BLOBs) in a single flow

Question

Hi everyone,

I’m creating a workflow in Alteryx that will call a Macro on a scheduled basis. The Macro receives the following inputs via a Text Input tool:

* Source Oracle table name

* Filter / WHERE clause (if applicable)

* Destination database/schema name in Snowflake

Normally, the Macro processing is straightforward: I use Input Data (Oracle) and Output Data (Snowflake) to establish connections, and a few Control Parameters allow the Macro to sequentially move a set of tables from Oracle to Snowflake.

However, this time I’m encountering some CLOB and BLOB fields that require additional processing, and I need some guidance.

I have two main questions:

* Dynamic routing based on data type
a) How can I analyze or parse an incoming table dynamically to identify the data types of each column?
b) Once the data types are identified, how can I route them to different pipelines for processing? For example:

* Text, Date, Number → Default Snowflake datatypes

* BLOB → Use the BLOB Convert tool

* CLOB

* Handling CLOBs
The sample table I tested on doesn’t have large CLOB values, but the workflow still times out at this step. I assume some additional processing is needed to move the CLOB. How should I handle this efficiently in Alteryx?

I’m relatively new to Alteryx and have only used a limited set of tools, so any tips, best practices, or example workflows for handling CLOBs and BLOBs in a scheduled Macro would be greatly appreciated.

Thank you in advance for your guidance!

SSaib · Answer

Hi Jay,
Thanks for your feedback and suggestions.

As recommended, I tried using the Field Info tool followed by a Filter to separate fields by datatype. Since this workflow is driven by a macro that processes different source tables dynamically, this approach seemed like a logical starting point. However, I’m still not entirely clear on how a Control Container would help in this case, as the Filter already segregates the data types. Here's what the current flow looks like:

Areas where I’m stuck

* Dynamically selecting columns

* After using Field Info + Filter, how do I dynamically capture the column names returned by each Filter condition and inject them into a SELECT statement to pull data from Oracle?
* Would this require another Input Data tool? If so, how would I use that?

Processing different datatypes
This is my current understanding of how each datatype might be handled:* NUMBER, VARCHAR2, DATE
Straightforward and can be moved directly without additional processing.
* CLOB
My thought process is:
* Run MAX(DBMS_LOB.GETLENGTH(CLOB_COLUMN))
* If the length is ≤ 4000, extract using
DBMS_LOB.SUBSTR(CLOB_COLUMN, 4000, 1)
* If the length is > 4000, break the CLOB into chunks before loading into Snowflake (this is my assumption and may be incorrect).

* BLOB
Use the BLOB Convert tool prior to loading into Snowflake.

Reassembling the data
My assumption is that each datatype group would feed into separate pipelines or temporary tables, which would then be joined back together at the end to recreate a single row in the Snowflake target table (matching the original Oracle row).* Is this the right way to think about it?
* If so, which Alteryx tools would be appropriate to recombine the data (Join, Union, Dynamic Rename, etc.)?
* This would need to happen for every row, which makes me wonder if I’m overcomplicating the design.

Example source tables

The Oracle source tables passed into the macro could look like any combination of the following:

* Table_1: NUMBER_COL, VARCHAR2_COL, DATE_COL
* Table_2: NUMBER_COL, CLOB_COL, DATE_COL
* Table_3: NUMBER_COL, BLOB_COL, STRING_COL, DOUBLE_COL

Each table is extracted via the macro and loaded into its corresponding table in Snowflake.

This feels like a common use case, so I may be overthinking or missing a simpler design pattern. I’d really appreciate any guidance or best practices for handling mixed datatypes in a macro-driven workflow.

Thanks again for your help.

jrlindem · Answer

@SSaib Interesting question.  Lots going on here.  It's been a while since I had to deal with CLOB's so I'm not going to be of much help there, but regarding your Field Types and Dynamic Handling, I would recommend you take a look at the [Field Info] Tool.  This will tell you the data types of your fields in table form.  Then you can use the [Filter] Tool along with [Control Container]'s for example, to drive logic based on the fields.

See if that gets you started, and if you have more specific questions from there, post a reply back here.  -Jay