Updating row selected by cursor

Be careful when porting applications that use this extension.According to the standard, the source value for a parenthesized sub-list of column names can be any row-valued expression yielding the correct number of columns.clause; columns not explicitly modified retain their previous values.

A cursor is a special kind of loop for traversing through an SQL resultset one row at a time.To maintain compatibility with legacy code, the configuration file UPDATE People SET firstname = 'Boris' WHERE lastname = 'Johnson'; UPDATE employee e SET salary = salary * 1.05 WHERE EXISTS( SELECT * FROM employee_project ep WHERE e.emp_no = ep.emp_no); UPDATE addresses SET city = 'Saint Petersburg', citycode = 'PET' WHERE city = 'Leningrad' UPDATE employees SET salary = 2.5 * salary WHERE title = 'CEO' For string literals with which the parser needs help to interpret the character set of the data, the introducer syntax may be used.The string literal is preceded by the character set name, prefixed with an underscore character: ”, will continuously update rows, over and over, and give the impression that the server has hung.Versions of Firebird from V.3 onward will comply with the standard.