
There is a special column _ROW that can be selected from any table.
The value of this column is a special string that contains all the column
values; i.e., a copy of the row@s internal representation.
This string can then be decomposed into the table and columns with the
row_table() and row_column() functions.

If the user does not have table-wide select privileges to the table
mentioned in the FROM clause of the SELECT that is accessing
_ROW, the code Diagnostics
42000 is returned as the SQL STATE for all operations
involving _ROW.  Separate privileges on all columns
do not suffice.

The _ROW is not updatable.
