Using prior and next - collection method, PL-SQL Programming

Assignment Help:

Using PRIOR and NEXT

The PRIOR(n) returns the index number that precede index n in a collection. The NEXT(n) returns the index number which succeed the index n. If n has no predecessor, then the PRIOR(n) returns NULL. Similarly, if n has no successor, then NEXT(n) returns NULL. The PRIOR and NEXT do not wrap from one end of a collection to another. For illustration, the statement below assigns a NULL to n as the first element in a collection has no predecessor:

n := courses.PRIOR(courses.FIRST); -- assigns NULL to n

The PRIOR is the inverse of NEXT. For illustration, if element i exists, the statement below assigns element i to itself:

projects(i) := projects.PRIOR(projects.NEXT(i));

You can use PRIOR or NEXT to traverse the collections indexed by any sequence of subscripts. In the example below, you use NEXT to traverse a nested table from that some elements have been deleted:

i := courses.FIRST; -- get subscript of first element

WHILE i IS NOT NULL LOOP

-- do something with courses(i)

i := courses.NEXT(i); -- get subscript of next element

END LOOP;


Related Discussions:- Using prior and next - collection method

Theory of special creation - origin of life, THEO R Y OF SPECIAL CREATION...

THEO R Y OF SPECIAL CREATION - Life originated on the earth due to natural events by the super natural power. The biblical story of creation of world within six days was p

Creating Views, Create a view named CustomerAddresses that shows the shippi...

Create a view named CustomerAddresses that shows the shipping and billing addresses for each customer in the MyGuitarShop database. This view should return these columns from the

Parameter and keyword description - select into statement, Parameter and Ke...

Parameter and Keyword Description: select_item: This select_item is a value returned by the SELECT statement, and then assigned to the equivalent variable or field in the

Multiple assignment - sql, Multiple Assignment- SQL SQL supports mult...

Multiple Assignment- SQL SQL supports multiple assignment to local variables and also applies multiple assignment semantics in SET clauses of UPDATE statements, but does not

Loop statements, LOOP Statements The LOOP statements execute a series o...

LOOP Statements The LOOP statements execute a series of statements at multiple times. The loops enclose the series of statements that is to be repeated. The PL/SQL provides typ

Sql operators, SQL Operators The PL/SQL uses all the SQL set, compariso...

SQL Operators The PL/SQL uses all the SQL set, comparison, and row operators in the SQL statements. This part briefly describes some of these operators.  1. Comparison Opera

Usefulness of data type, Usefulness of Data Type In SQL, as in most c...

Usefulness of Data Type In SQL, as in most computer languages, a type can be used for constraining the values that are permitted to be used for some purpose. In particular, i

Translate the given er schema into sql, Consider the schema for FreeCheckin...

Consider the schema for FreeChecking Bank, that we designed given below. Translate the given ER schema into SQL CREATE TABLE statements (indicating primary key, unique and foreign

Write a program to implement inverted file shown slider, Write a program to...

Write a program to implement the inverted file shown in the slides (Simple Index file, LabelID file and Data file).  Use the Avail_List to point at the deleted Label IDs so that th

Using commit, Using COMMIT The COMMIT statements end the present trans...

Using COMMIT The COMMIT statements end the present transaction and make permanent any changes made during that transaction. Till you commit the changes, other users cannot acc

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