PostgreSQL中，有一种 tidscan。当我在使用cursor的时候，会用到此种scan：
[postgres@lex pgsql]$ cat ./data/test.sqlCREATE OR REPLACE Function FindCourse ( name_in IN varchar ) RETURNS integer LANGUAGE plpgsql AS $$ DECLARE cnumber integer; c1 CURSOR FOR SELECT course_number, instructor from course_tbl where course_name = name_in FOR UPDATE; BEGIN BEGIN open c1; fetch c1 into cnumber; IF not found THEN cnumber := 9999; ELSE UPDATE course_tbl SET instructor = 'SMITH' WHERE CURRENT OF c1; COMMIT; END IF; close c1; EXCEPTION WHEN OTHERS THEN END; RETURN cnumber; END;$$; [postgres@lex pgsql]$
下面再进行一下修正：
在PostgreSQL的 function 里面，是不允许进行commit的。所以其实，上面的程序需要改成：
[postgres@lex pgsql]$ cat ./data/test.sqlCREATE OR REPLACE Function FindCourse ( name_in IN varchar ) RETURNS integer LANGUAGE plpgsql AS $$ DECLARE cnumber integer; c1 CURSOR FOR SELECT course_number, instructor from course_tbl where course_name = name_in FOR UPDATE; BEGIN BEGIN open c1; fetch c1 into cnumber; IF not found THEN cnumber := 9999; ELSE UPDATE course_tbl SET instructor = 'SMITH' WHERE CURRENT OF c1; END IF; close c1; EXCEPTION WHEN OTHERS THEN END; RETURN cnumber; END;$$; [postgres@lex pgsql]$
