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

Benefit of the dynamic sql pl sql, Benefit of the dynamic SQL: This pa...

Benefit of the dynamic SQL: This part shows you how to take full benefit of the dynamic SQL and how to keep away from some of the common pitfalls. Passing the Names of Sc

What is a collection, What Is a Collection The collection is an ordered...

What Is a Collection The collection is an ordered group of elements, all of similar type (for e.g. the grades for a class of students). Each element has a unique subscript whic

Exit statement - syntax, EXIT Statement   You can use the EXIT stateme...

EXIT Statement   You can use the EXIT statement to exit a loop. The EXIT statement has 2 forms: the conditional EXIT WHEN and the unconditional EXIT. With the either form, you

Structure of an object type in pl/sql, Structure of an Object Type: Si...

Structure of an Object Type: Similar to package, an object type has 2 parts: the specification and the body. The specification is the interface to your applications; it declar

How to use the explain plan for statement, Using the student and faculty ta...

Using the student and faculty tables create a select query that outputs all students for a specific advisor. Generate the execution plan, select out the explain plan . Create an

Data abstraction, Data Abstraction The Data abstraction extracts the im...

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

Using operator deref - manipulating objects in pl sql, Using Operator DEREF...

Using Operator DEREF: You cannot navigate through refs within the PL/SQL procedural statements. Rather than, you should use the operator DEREF in the SQL statement. The DEREF

Example of alternative formulation as a table constraint, Example of Altern...

Example of Alternative formulation as a table constraint Example: Alternative formulation as a table constraint ALTER TABLE EXAM_MARK ADD CONSTRAINT Must_be_enrolled_to_

Return statement, RETURN Statement The RETURN statement instantly compl...

RETURN Statement The RETURN statement instantly completes the execution of a subprogram and returns control to the caller. The Execution then resumes with the statement below t

Dynamic sql - pl sql, Dynamic SQL: The Most PL/SQL programs do a predi...

Dynamic SQL: The Most PL/SQL programs do a predictable, specific job. For illustration, a stored procedure may accept an employee number and salary increase, and then update t

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