Meaning of database upgrade message: DBD::mysql::st execute failed: Unknown column '<column-name>' in '<table-name>'


In this case, ‘Unknown column’ means ‘expected column not found’, or ‘known
column missing’, from the point of view of the database conversion program.

It does not mean ‘an unexpected column was found’, or ‘a column unknown to
me was found’.

Well, perhaps there will be someone else for whom this was not utterly