Write to table with user defined type


I've recently started using KNIME and although different, it's a very impressive tool.

I've got a question though: I have a table in Postgres that uses a user defined type. In this case, it's a type for gender - the options are 'M', 'F','U'. KNIME has the column defined as string (which is fine in principle). However, the table writer complains that "ERROR: column "gender" is of type o_wh.geslacht but expression is of type character varying". I cannot seem to change the columntype to ENUM. What is even more weird: I get the insert-statement returned (not strange) and when I execute that statement in PGAdmin, it inserts the record without a problem. It looks like KNIME is doing a final check on metadata (but it's wrong in its assumptions)... Is there a way to just execute the inserts without KNIME (partially) checking on metadata?

What to do?

Kind regards,


You should be able to get around such things by using the sql execute node instead.

Use the postgresql enum-casting syntax in your SQL. So if you would have an insert statement like this:

  insert into xx(gender) values('M')

that should become

  insert into xx(gender) values('M'::geslacht)


Then get your values in the sql instead of hardcoding the value and use the sql inject and or sql executor to get it going.

Hi Ellert,

thanks - I'll give it a try!