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

Manipulating objects in pl sql, Manipulating Objects: You can use an o...

Manipulating Objects: You can use an object type in the CREATE TABLE statement to indicate the datatype of a column. When the table is created once, you can use the SQL statem

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

Selecting objects in pl sql, Selecting Objects: Suppose that you have ...

Selecting Objects: Suppose that you have run the SQL*Plus script below that creates object type Person and object table persons, and that you have settled the table: CREATE

Inner join, Inner Join We have learned how to retrieve data from one t...

Inner Join We have learned how to retrieve data from one table by using SELECT statement. But, as we have learned, normalized relational databases mean the data is spread betw

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

Creating a table, Creating a Table Syantax: CREATE TABLE ENROL...

Creating a Table Syantax: CREATE TABLE ENROLMENT (StudentId SID, Name   VARCHAR (30) NOT NULL, CourseId CID, PRIMARY KEY (StudentId, CourseId)) ; Explan

Build a purchases report that matches the general ledger, Great Plains (Mic...

Great Plains (Microsoft Dynamics) Purchases Report Project Description: I want to build a purchases report that matches the General Ledger. presently, when I join the PM20

Declaring and initializing objects in pl/sql, Declaring and Initializing Ob...

Declaring and Initializing Objects: An object type is once defined and installed in the schema; you can use it to declare the objects in any PL/SQL, subprogram, block or packa

Parameter modes - pl sql, Parameter Modes: You do not require to speci...

Parameter Modes: You do not require to specify a parameter mode for the input bind arguments (those used, for illustration, in the WHERE clause) as the mode defaults to IN. Th

Committing and rolling back - autonomous transaction, Committing and Rollin...

Committing and Rolling Back The COMMIT and ROLLBACK end the active autonomous transaction but do not exit the autonomous routine. As the figure shows, if one transaction ends,

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