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

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

Entering and exiting - autonomous transaction, Entering and Exiting If...

Entering and Exiting If you enter the executable part of an autonomous routine, the major transaction suspends. When you exit the routine, the major transaction resumes. To ex

I need simple hosted sql database, Project Description: I want a small r...

Project Description: I want a small relational database to be built. I want the database to have the subsequent information tables: Employee Information Document storage

Advantages of wrapping, Advantages of Wrapping   The PL/SQL Wrapper co...

Advantages of Wrapping   The PL/SQL Wrapper convert the PL/SQL source code into a transitional form of the object code. By hiding the application internals, the Wrapper secure

Example of not exists in sql, Example of NOT EXISTS in SQL Example: Us...

Example of NOT EXISTS in SQL Example: Use of NOT EXISTS CREATE ASSERTION Must_be_enrolled_to_take_exam_alternative1 CHECK ( NOT EXISTS (SELECT StudentId, CourseId

Components of an object type - attributes in pl/sql, Attributes: Just ...

Attributes: Just similar to variable, an attribute is declared with a name and datatype. The name should be exclusive within the object type. The datatype can be any Oracle ty

Forall statement - syntax, FORALL Statement The FORALL statements instr...

FORALL Statement The FORALL statements instruct the PL/SQL engine to bulk-bind the input collections before sending them to the SQL engine. Though the FORALL statement consists

Cursor for loops, Cursor FOR Loops In most cases that need an explicit ...

Cursor FOR Loops In most cases that need an explicit cursor, you can simplify the coding by using a cursor FOR loop rather of the OPEN, FETCH, and CLOSE statements. A cursor FO

Example of unwrap operator - sql, Example of UNWRAP Operator - SQL Exa...

Example of UNWRAP Operator - SQL Example here shows how unwrapping can be done in longhand in SQL. Example: Unwrapping in SQL Letting CONTACT_INFO_WRAPPED denote the res

%isopen - explicit cursor attributes, %ISOPEN The %ISOPEN yields TRUE ...

%ISOPEN The %ISOPEN yields TRUE if its cursor or cursor variable is open; or else, the %ISOPEN yields FALSE. In the illustration, you use the %ISOPEN to select an action:

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