Understanding nested tables, PL-SQL Programming

Assignment Help:

Understanding Nested Tables

Within the database, the nested tables can be considered as one-column database tables. The Oracle stores the rows of a nested table in no specific order. But, when you retrieve the nested table into the PL/SQL variable, the rows are given consecutive subscripts starting at 1. That provides you array-like access to the individual rows.

Within PL/SQL, the nested tables are like one-dimensional arrays. Though, nested tables differ from arrays in two significant ways. Firstly, the arrays have a fixed upper bound, but nested tables are unbounded .Therefore, the size of a nested table can increase dynamically.

 

150_Understanding Nested Tables.jpg

                                   Figure: Array versus Nested Table


Secondly, the arrays should be dense (having consecutive subscripts). Therefore, you cannot delete individual elements from an array. Initially, the nested tables are dense, but they can be sparse (having nonconsecutive subscripts). And hence, you can delete elements from a nested table using the built-in procedure DELETE. That might leave gaps in the index, but the built-in function NEXT iterate over any series of subscripts.


Related Discussions:- Understanding nested tables

%found - explicit cursor attributes, %FOUND Subsequent to a cursor or ...

%FOUND Subsequent to a cursor or cursor variable is opened but before the first fetch, the %FOUND yields NULL. Afterward, it yields TRUE when the last fetch returned a row, or

Semijoin and composition - sql, Semijoin and Composition - SQL For sem...

Semijoin and Composition - SQL For semijoin, the dyadic relational operator MATCHING, defined thus: r1 MATCHING r2, where r1 and r2 are relations such that r1 JOIN r2 is de

Creating a sql file, Creating a SQL file 1. Open a new file in Notepad...

Creating a SQL file 1. Open a new file in Notepad++ and save it to the location c:\mysql\bin, with the name lab8script.sql (the file extension should be .sql ). Add a MySQL co

Program, heap sort program in pl/sql

heap sort program in pl/sql

Data types in sql - integer, Data Types in SQL - Integer INTEGER or  s...

Data Types in SQL - Integer INTEGER or  synonymously INT, for integers within a certain range. SQL additionally has types SMALLINT and BIGINT for certain ranges of integers. T

Rephrase conditional control statements, Rephrase Conditional Control State...

Rephrase Conditional Control Statements When computing a logical expression, the PL/SQL uses short-circuit evaluation. That is, the PL/SQL stops evaluating the expression as s

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

Passing cursor parameters, Passing Cursor Parameters You use the OPEN ...

Passing Cursor Parameters You use the OPEN statement to pass the parameters to a cursor. Unless you want to accept the default values, each proper parameter in the cursor decl

Defining records, Defining and Declaring Records To create records, yo...

Defining and Declaring Records To create records, you have to define a RECORD type, and then declare records of that type. You may also define RECORD types in the declarative

Managing cursors, Managing Cursors The PL/SQL uses 2 types of cursors: ...

Managing Cursors The PL/SQL uses 2 types of cursors: implicit and explicit. The PL/SQL declares a cursor implicitly for all the SQL data manipulation statements, including th

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