Varrays versus nested tables, PL-SQL Programming

Assignment Help:

Varrays versus Nested Tables

The Nested tables are differing from varrays in the following ways:


1)  Varrays have a maximum size, while nested tables do not.

2)  Varrays are always dense, while nested tables can be sparse. Therefore, you can delete individual elements from a nested table but not from a varray.

3) The Oracle stores varray data in-line (in similar tablespace). But, the Oracle stores nested table data out-of-line in a store table, that is a system-generated database table related with the nested table.

4) When stored in the database, the varrays retain their ordering and subscripts, while nested tables do not.


Which collection type must you use? That totally depends on your wants and the size of the collection. The varray is stored as an opaque object, while a nested table is stored in a storage table with each element mapped to a row in the table. Therefore, if you want efficient queries, then use the nested tables. If you want to retrieve the whole collections as a whole, then use varrays. Though, when collections get very large, it becomes impractical to retrieve more than subsets. Therefore, varrays are better suited for the small collections


Related Discussions:- Varrays versus nested tables

Heap sort algorithm in pl sql, I want to implement heap sort algorithm in p...

I want to implement heap sort algorithm in pl sql please share the source code for guidance

Using %rowtype-declarations in sql, Using %ROWTYPE The %ROWTYPE attribut...

Using %ROWTYPE The %ROWTYPE attribute gives a record type which represents a row in a table (or view). The record can store the whole row of data selected from the table or fetc

Origin of earth - big bang hypothesis, ORIGIN OF EARTH - BIG-BAN G HY...

ORIGIN OF EARTH - BIG-BAN G HYPOTHESIS - Origin of life is linked to origin of earth. Cosmos, the Universe originated 10-20 billion years ago by Big Bang (thermonu

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

Python function, This task involves developing some functions that extract ...

This task involves developing some functions that extract data from an SQL database. The scenario is that a company which owns an online vehicle search website wants to generate so

Parameter & keyword description - functions, Parameter & Keyword Descriptio...

Parameter & Keyword Description: function_name: The user-defined function is identifying by that keyword. parameter_name: This identifies the formal parameter that

EXCEPTION handling, set serveroutput on declare a number(5); b numb...

set serveroutput on declare a number(5); b number(5); c number(5); begin a:=&a; b:=&b; c:=a/b; dbms_output.put_line(c); exception when zero_divide then d

Primary key, PRIMARY KEY: PRIMARY KEY  indicates that the table is sub...

PRIMARY KEY: PRIMARY KEY  indicates that the table is subject to a key constraint, in this case declaring that no two rows in the table assigned to ENROLMENT can ever have the

Using set transaction, Using SET TRANSACTION You use the SET TRANSACTI...

Using SET TRANSACTION You use the SET TRANSACTION statement to begin the read-only or read-write transaction, start an isolation level, or assign your present transaction to a

Update command- sql, UPDATE Command- SQL Loosely speaking, UPDATE chan...

UPDATE Command- SQL Loosely speaking, UPDATE changes some of the column values of some existing rows of its target table. Thus, although some rows disappear from the target an

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