Is it possible to use a dynamic writer to update? I want to read multiple feature classes, join each feature class and then update the joined records in a different database. Matching columns are not available when selecting Update feature opera

Yes this is possible. You're right, the attributes wouldn't be available on the writer parameters because the dynamic writer doesn't know what they're going to be until runtime.

So I think you have two choices:

• Manually expose the attributes using the AttributeExposer transformer
• Instead of picking the attributes, make a where clause in an attribute (like myWhereClause: myAttribute = myFieldName) and use that as a WHERE clause instead of a Match Column

Hope this helps.