12. Data structures and internal tables

Question 1

Structures

Answer 1

Temporary objects in program memory. Structures are used in connection with sequential datasets and subroutines as well as a “staging area” for internal tables.

Question 2

Internal Tables

Answer 2

Internal tables are comprised of records which have the same format as an individual structure.
Internal tables are tables which only exist during the execution of a program.
Unlike the ABAP Dictionary transparent tables, internal table data is not stored on the database server. Internal table data resides in a program specific work area.

Question 3

BEGIN OF / END OF

Answer 3

The start and end of the structure are indicated by BEGIN OF and END OF .

Question 4

Types of internal tables

Answer 4

Standard, Sorted and Hashed

Question 5

APPEND

Answer 5

APPEND statement uses the work area to append the line/row information into the table.

Question 6

SY-TABIX statement

Answer 6

Row number in the table index of an internarl table. Contains the last row accessed using a primary or secondary table index. Is set to 0 when accessed using a hash algorithm.
When an internal table is read, the system field SY-TABIX is set to the index value of the internal table line which has been placed either in the header line or the work area

Question 7

COLLECT

Answer 7

When the COLLECT statement is used, ABAP scans the internal table for entries which correspond to the header line in fields which are not of type P, I or F . E

Question 8

SORT Statement

Answer 8

An internal table is sorted using the SORT statement. If sort criteria is not specified, the table is sorted by all fields (except those of data types P, I, and F) in ascending order in the sequence in which they were declared.

Question 9

An internal table type is defined

Answer 9

using the TYPES statement. No memory is allocated when defining a type.

Question 10

An internal table object is created with

Answer 10

the DATA statement by referring to an internal table type using the TYPE parameter. It is this DATA statement occupies memory. Internal table objects can also be created through a reference to an existing table or structure using the LIKE parameter.

Question 11

implicit key

Answer 11

By default, all the records that you append to your internal table have a key. This key is the combination of all non-numeric fields. This is the implicit key.

Question 12

Control Level Processing

Answer 12

When processing an internal table with the LOOP statement, it is possible to add additional code that will only be processed when a field changes.

Question 13

READ TABLE

Answer 13

reads a single table entry.

Question 14

READ TABLE WITH KEY ‘‘.

Answer 14

• Enter the search argument after the parameter KEY (in single quotes).
  
  • Beginning with the first character of the first field of the first entry in the table, ABAP compares each record character by character with the search argument (‘‘).

Question 15

READ TABLE WITH KEY ‘‘ BINARY SEARCH.

Answer 15

• Like variant 2, but using a binary search (faster than linear search).
• The internal table must be sorted in ascending order by the
search argument.

Question 16

INSERT INDEX <i></i>

Answer 16

Statement generates a new table entry before line <i> with the contents of the header line. If the table has no entries, the contents of the header line are added to the table. </i>

Question 17

MODIFY INDEX <i></i>

Answer 17

Statement overwrites table line <i> with the contents of the header line. Line <i> must already exist. Ex.</i></i>

Question 18

DELETE INDEX <i></i>

Answer 18

statement deletes table line <i>. Ex.</i>

Question 19

APPEND TO

Answer 19

Appends the contents of the work area to the end of the internal table Ex.

Question 20

COLLECT INTO

Answer 20

Accumulates the values on a field into the table.

Question 21

INSERT INTO

Answer 21

Inserts a new line with the contents of the work area before the current line.

Question 22

MODIFY FROM

Answer 22

Overwrites a line in the table with the contents of the work area.

Question 23

READ TABLE INTO

Answer 23

Reads a line from the table into the work area.

Question 24

LOOP AT INTO

Answer 24

Processes an internal table. On each loop pass, a table entry is placed in the work area.

Question 25

CLEAR

Answer 25

statement initialises all single fields in the header line of an internal table according to type.

Question 26

REFRESH

Answer 26

Statement deletes all table lines. The table storage space is not released. The header line remains unchanged.

Question 27

FREE

Answer 27

Statement releases the storage space required for a table. The header line remains unchanged. Ex.

Question 28

DESCRIBE TABLE

Answer 28

The DESCRIBE TABLE statement provides information about an internal table’s attributes. With this statement, the programmer must use at least one of the two parameters available – LINES and OCCURS.

Question 29

LINES

Answer 29

The LINES parameter allows the programmer to find out the number of existing table entries.

Question 30

OCCURS

Answer 30

The OCCURS parameter contains the value of the OCCURS clause specified in the internal table definition.

Question 31

EDITOR-CALL FOR

Answer 31

With the EDITOR-CALL FOR statement, the program will
open the SAP Table Editor which allows the user to change any data in the
internal table.