Already have an account? Get multiple benefits of using own account!
Login in your account..!
Remember me
Don't have an account? Create your account in less than a minutes,
Forgot password? how can I recover my password now!
Enter right registered email to receive password!
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
pos1 INTEGER := 1;
pos2 INTEGER := 0;
cum INTEGER;
cum := pos1 + pos2;
FOR i IN 3..n LOOP
pos2 := pos1;
pos1 := cum;
END LOOP;
RETURN cum;
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.
Overloading: Similar to packaged subprograms, methods of the same type can be overloaded. That is, you can use similar name for various methods if their formal parameters diff
Keyword & Parameter Description: PRAGMA: These keywords signify that the statement is a pragma (i.e. compiler directive). The Pragmas are processed at the compile time, n
Data Abstraction The Data abstraction extracts the important properties of data while ignoring the not necessary details. Once you design a data structure, you can fail to reme
Procedural Constraint Enforcement (Triggers) SQL has an alternative method of addressing database integrity, involving event-driven procedural code. The special procedures th
Expressions An expression is a randomly complex combination of the constants, variables, literals, operators, & function calls. The simplest expression is the single variabl
Implicit Cursors The Oracle implicitly opens a cursor to process each SQL statement not related with an explicitly declared cursor. The PL/SQL lets you refer to the most recen
Using TRIM This process has two forms. The TRIM removes an element from the end of the collection. The TRIM(n) removes the n elements from the end of the collection. For e.g.
Table Literals - SQL One might expect SQL to support table literals in the manner illustrated in Example 2.2, but in fact that is not a legal SQL expression. Example: Not a
Use Serially Reusable Packages To help you to manage the use of memory, the PL/SQL gives the pragma SERIALLY_ REUSABLE that mark some packages as serially reusable . So mark
Referencing Records Unlike the elements in a collection, that are accessed using subscripts, the fields in a record are accessed by name. To reference an individual field, you
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!
whatsapp: +91-977-207-8620
Phone: +91-977-207-8620
Email: [email protected]
All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd