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

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

Goto statement - syntax, GOTO Statement   The GOTO statement branches ...

GOTO Statement   The GOTO statement branches categorically to a block label or statement label. The label should be exclusive within its scope and should precede a PL/SQL bloc

Package dbms pipe in pl/sql, DBMS_PIPE: The Package DBMS_PIPE allows va...

DBMS_PIPE: The Package DBMS_PIPE allows various sessions to communicate over the named pipes. (A pipe is a region of memory used by one of the process to pass information to

Opening a cursor, Opening a Cursor Opening the cursor executes the que...

Opening a Cursor Opening the cursor executes the query & identifies the result set that consists of all rows that meet the query search criteria. For the cursors declared usin

Understanding varrays, Understanding Varrays The Items of type VARRAY ar...

Understanding Varrays The Items of type VARRAY are termed as the varrays. They permit you to relate a single identifier with the whole collection. This relationship lets you man

Data types in sql - decimal, Data Types in SQL - Decimal DECIMAL, NUME...

Data Types in SQL - Decimal DECIMAL, NUMERIC, REAL, FLOAT and various other terms for various sets of rational numbers. When these key words are specified for the declared typ

Name resolution-naming conventions, Name Resolution In potentially uncer...

Name Resolution In potentially uncertain SQL statements, the names of the database columns take precedence over the names of the local variables and formal parameters. For e.g.

Exit-when - iterative control, EXIT-WHEN The EXIT-WHEN statement permits...

EXIT-WHEN The EXIT-WHEN statement permits a loop to complete conditionally. Whenever the EXIT statement is encountered, the condition in the WHEN clause is computed. When the co

Need for dynamic sql - pl sql , Need for Dynamic SQL: You need dynamic...

Need for Dynamic SQL: You need dynamic SQL in the situations as follows: 1) You would like to execute a SQL data definition statement (like CREATE), a data control statemen

Updating objects in pl sql, Updating Objects: To change the attributes...

Updating Objects: To change the attributes of objects in an object table, you can use the UPDATE statement, as the illustration below shows: BEGIN UPDATE persons p SET p

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