Recursion versus iteration, PL-SQL Programming

Assignment Help:

Recursion versus Iteration

Dissimilar the iteration, recursion is not crucial to PL/SQL programming. Any problem which can be solved using recursion can be solving using the iteration. Also, the iterative version of the subprogram is typically easier to design than the recursive version. Though, the recursive version is typically simpler, smaller, and hence easier to debug. Compare the functions below that calculate the nth Fibonacci number:

-- recursive version

FUNCTION fib (n POSITIVE) RETURN INTEGER IS

BEGIN

IF (n = 1) OR (n = 2) THEN

RETURN 1;

ELSE

RETURN fib(n - 1) + fib(n - 2);

END IF;

END fib;

-- iterative version

FUNCTION fib (n POSITIVE) RETURN INTEGER IS

pos1 INTEGER := 1;

pos2 INTEGER := 0;

cum INTEGER;

BEGIN

IF (n = 1) OR (n = 2) THEN

RETURN 1;

ELSE

cum := pos1 + pos2;

FOR i IN 3..n LOOP

pos2 := pos1;

pos1 := cum;

cum := pos1 + pos2;

END LOOP;

RETURN cum;

END IF;

END fib;

The recursive version of the Fibonacci is more graceful than the iterative version. Though, the iterative version is more accurate; it runs faster and uses less storage. That is as each recursive call needs an additional time and memory. As the number of recursive calls gets bigger, so does the difference in effectiveness. Still, if you expect the number of recursive calls to be little, you may choose the recursive version for its readability.


Related Discussions:- Recursion versus iteration

Character types, ROWID and UROWID Internally, every database table has ...

ROWID and UROWID Internally, every database table has a ROWID pseudo column that stores binary values known as rowids. Each rowid shows the storage address of a row. A physical

Write a program, to write a heap sort program usin pl-sql

to write a heap sort program usin pl-sql

Query, ALTER TABLE bb_basketitem ADD CONSTRAINT bitems_qty_ck CHECK (quan...

ALTER TABLE bb_basketitem ADD CONSTRAINT bitems_qty_ck CHECK (quantity BEGIN INSERT INTO bb_basketitem VALUES (88,8,10.8,21,16,2,3); END; Brewbean’s wants to add a check

Predefined exceptions, Predefined Exceptions The internal exception is ...

Predefined Exceptions The internal exception is raised implicitly whenever your PL/SQL program exceeds a system-dependent limit or violates an Oracle rule. Each & every Oracle

Package body in pl/sql, Package Body: The package specification is imp...

Package Body: The package specification is implemented by the package body. That is, the package body has the definition of every cursor and the subprogram declared in the pac

Data types and representations, Data Types and Representations This ex...

Data Types and Representations This explains the concept possible representation, abbreviated possrep, and explains how these can be used in conjunction with constraints to de

Cursors, What is Cursors how to use it in Real time application ?

What is Cursors how to use it in Real time application ?

Union all - sql, UNION ALL - SQL Further varieties of UNION arise when...

UNION ALL - SQL Further varieties of UNION arise when we replace the key word DISTINCT by ALL in any of the foregoing examples, as in Example. ALL specifies that if row r appe

Pl/sql engine, Architecture The PL/SQL run-time system and compilation ...

Architecture The PL/SQL run-time system and compilation is a technology, not an independent product. Consider this technology as an engine that compiles and executes the PL/SQL

produce vertical output format- oracle, Create a Oracle procedure to produ...

Create a Oracle procedure to produce vertical output format when selecting rows from a database table.

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd