DSXchange

We are using a Teradata Enterprise stage with custom sql query. The metadata for this query is retrieved through "plug In Metadata". One of these column DataType is VARCHAR and length is 255 in table.
After extraction through teradata enterprise stage, next we used a transformer to change the length of column from Varchar(255) to only varchar(40) and next write it back to a target dataset with varchar(40) defined in column metadata. Jobs runs fine successfully. But when we look at the DataSet management of the target dataset , still it show's VARCHAR(255).
column lenght not overwritten ? No warning or error. It still inherits the length of table metadata, though it is declared as VARCHAR(40) in Dataset stage. Is that the way it works ?

Do we have to use any modify stage to convert from Varchar(255) to Varchar(40), before target DataSet, to stop taking what ever is in Teradata Enterprise stage metadata by a DataSet.

Thanks,