Exercise

Set - 1

Question 1 :

What is the difference between internal table and structure?

Answer :

There are there types of structure:-
1. Flat structure( elementary fields)
2. Nested structure ( type reference to other structure)
3. deep structure ( type reference to database tables)


Question 2 :

Explain row type and line type concept ?

Answer :

line type refers to the structure of an internal table,whereas row type is the actual part that contains the data and it refers to the table body.creating internal table using line type and row type concept is for reusability purpose.Line type and Row type are defined at DDIC LEVEL.


Question 3 :

Can any one give me brief explanation about internal tables, and work area ?

Answer :

*An internal table is a run time instance. It get created when program starts execution.
*It get destroyed when program terminates. It has two different parts: HeaderLine(optional) and Body(Compulsory).
*Any value that comes to or goes from interanal table, that travels through headerline.


Question 4 :

Size of the internal tables?

Answer :

The size of the internal tables are set using the 'occurs n' clause. Here n refers to a integer number that specifies the size. Usually its given as 'occurs 0' which creates an itab with the memmory space of 8kb.


Question 5 :

What is the basic difference internal tables and database tables? How can we differentiate by looking at the tables? Handling of internal tables ?

Answer :

The basic difference is database tables are stored in DB server
and the internal tables are virtual tables these are created run time only
Internal tables are created dynamically, the memory of internal tables is not
permant memory, for internal tables the memory will be created in the application server and it is external memory and terminates after the program termination.


Question 6 :

How to eliminate duplicate entries in internal tables?

Answer :

Answer1:
SORT itab.DELETE ADJACENT DUPLICATES FROM itab COMPARING ALL FIELDS. 

Answer2:
The following syntax: 
SORT itab <fieldname>. 
delete adjcent duplicates from itab comparing .