The documentation for the tables and columns commands in the tdbc::connection manpage contains the following text:

"It may contain the SQL wild-card characters '%' and and whose values are subdictionaries."

I think it should read

"It may contain the SQL wild-card characters WHICH ONES?  The result of the command is a dictionary whose keys are table names and whose values are subdictionaries."

(WHICH ONES to be replaced by the wild card chars that are supported.)

Above for the tables command. Analogous issue exists for the columns command.