internal table udemy

8/17/2019 Internal Table Udemy

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INTERNAL TABLE

Temporary table stored in RAM on the application

server .

Created and filled by program and dies down when theprogram ends .

Consists of one or more rows with identical structure .


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Body

Header Line

Structure of an Internal Table

Body holds the rows in internal table . Header line is a field string identical to a row in the body . It is a buffer used to hold

each data before it is added to the body or retrieved from an

internal table


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Internal tables can exist both as data types and as data

objects .

Data type:-Abstract description of an internal table, either

in a program or centrally in the ABAP Dictionary, that is

used to create a concrete data object. The data type is

also an attribute of an existing data object.


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Internal Table as Data Type

Specified by : Line Type , Key and Table Type

Line Type : Declaration of the type of each row in internal table type .Can be any simple elemental data type (C,D,P,F etc) , or a

structure(each component of the structure becomes a column in the

internal table) , or it can be another internal table itself .

Key :Identifies table rows. Basically of two kinds - the standard key anda user-defined key and may be UNIQUE or NON-UNIQUE. For tables

with structured line type, the default key consists of all of its non-numerical columns that are not references or themselves internal tables.

For those with elementary line type, the default key is the entire line.

The default key is empty whose line type is an internal table


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TableType

Determines how ABAP will access individualtable entries.

Type Presence of

Index

Key

mention

mandatory

(U)nique/

(N)on-unique

Record

Access

Response

Time For

Key Access

Standard Y N N By indexor by key

Prop. To no.of table

entries

Sorted Y Y Both By index

or by key

Logarithmic

ally prop. To

no. of tableentries

Hashed N Y U By key Independent

of entries


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Internal Table As Data Objects

Internal Tables as Data objects are defined either with the

data type of an internal table, or directly as an internal table,

are always fully defined in respect of their line type, key and

access method.

The maximum memory that can be occupied by an internal

table (including its internal administration) is near about 2

gigabytes

Hashed tables may not contain more than 2 million entries.The line types of internal tables can be - elementary,

structured, or internal tables. The individual lines are called

table lines or table entries. Each component of a structured

line is called a column in the internal table.


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Creating Internal Tables

Two Options Are Available :-

Declaring internal tables as abstract data types in programsor in the ABAP Dictionary, and then to use them to define

data objects.

Defining Internal Tables Directly as data objects.


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Creating Internal Table Types

Syntax :- TYPES TYPE|LIKE OF [WITH]

[INITIAL SIZE ].

t is the name of the internal table typeTabkind is the type of table : standard / sorted/hashed

Linetype defines the data type of individual line , whichcan be elementary(C,P,F etc) or a structure

n specification of the initial amount of mainmemory assigned to an internal table object


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Key

[UNIQUE|NON-UNIQUE] KEY ...

Used for internal tables with flat/nested structures as line

type .

[UNIQUE|NON-UNIQUE] KEY TABLE LINEUsed mainly for tables whose line type is elementary ( C , P

,F,I etc , for them the entire line is the key) or for structures(

U can specify all components in the structure as key) .

[UNIQUE|NON-UNIQUE] DEFAULT KEYDeclares the fields of the default key as the key fields.


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Few Examples on Internal Table Type

TYPES: BEGIN OF MATERIAL,

MATNR(12) TYPE C,

DESCRIP(30) TYPE C,

STOCK TYPE I,

END OF MATERIAL.

TYPES IMAT TYPE SORTED TABLE OF MATERIAL WITH UNIQUE

KEY MATNR .

TYPES IMAT2 TYPE STANDARD TABLE OF MATERIAL WITH

DEFAULT KEY.

TYPES rollno TYPE HASHED TABLE OF I WITH UNIQUE KEYTABLE LINE.


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Creating Internal Table As Data Objects

TYPES: BEGIN OF MATERIAL,

MATNR(12) TYPE C,

DESCRIP(30) TYPE C,

STOCK TYPE I,

END OF MATERIAL.

TYPES IMAT TYPE SORTED TABLE OF MATERIAL WITH UNIQUE

KEY MATNR .

DATA : INT_MATERIAL LIKE IMAT WITH HEADER LINE .

Creating With Reference To Internal Table Types


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Declaring New Internal Tables

DATA IMAT TYPE HASHED TABLE OF MARA WITH

UNIQUE KEY MATNR.

Data : Begin of transaction ,

matnr like mseg-matnr ,

Mblnr like mseg-mblnr ,

Werks like mseg-werks ,

menge like mseg-menge ,

end of transaction .

Data int_trans like sorted table oftransaction with unique key matnr with

header line .


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data : begin of int_mseg occurs 100 ,

matnr like mseg-matnr ,

werks like mseg-werks ,lgort like mseg-lgort ,storing type I ,end of int_mseg .

(Creates an internal table with header line )

Internal Table Declared On Earlier ReleasesWithout Any Key and Without Any Table Type


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OPERATIONS ON INTERNAL TABLE

Initializing

Populating

FetchingData

UpdatingData

DeletingData

Single Multiple


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Initializing Internal Tables

Clear

clear .

clear [ ] ( To clear the body of

internal table with header line)

Refresh

refresh itab ( applies to the body of table)

Free

free .

Releases the memory allocated to internal table


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Operations For All Table Types


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Inserting Records

Single Line Insertion :

Insert into table

The record is appended at the end for standard table .

For sorted table , record is appended according to the key .

For table with non unique keys , if any entry with same

value of keys exist , the new record is placed above theexisting entry with the same key .

For hashed table, record is inserted according to the table

key


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Inserting Several Lines :-

Insert lines of [ from ] [to ]into table .

Insertion by Collect Statement :-

Collect statement inserts new records where table keymatch is not found /groups records as per the tablekey if all the non-key columns are numeric .

Inserting Records with MOVE Statement :

Move to .

= .

Use [] to refer to the body of the internal tables with

header line .


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Inserting Records into Internal table by SQLStatement :-

Select .. .. Into corresponding fields of table

from …….where ……

(selects records from database tables and fills in the body of the

internal table )

Select .. .. Into corresponding fields of

from …….where ……

(selects records from database tables and fills in the header line of

the internal table )Select .. .. appending corresponding fields

of table from …….where ……

(selects records from database tables and appends them with the pre

existing contents of the internal table )


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Fetching Records From Internal Table

Read table .

The key can be table key or other keys .

Search Using Table Key : Read table from [into ].

Read table with table key

= = [ into ]

Linear search for standard table , Binary search for sorted

table and search using hashing algorithm takes place for

hashed table .If no key is defined , no record will be

fetched .


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Using Different Search Key :Read table with key = [into wa] .

Read table with key = = :f2> [into

wa]

Read table into [comparing|transporting ……|all fields|no fields]

Reading into Field Symbol :

Read table assigning .


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Examples :-

Wa-col1 = 2 .

Wa-col2 = ‘Subhendu’ .

Read table itab from wa into wa .Read table itab from wa into wa comparing

col2 .

Read table itab with table key col1 = 45 intowa transporting col2 .


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Sorting Internal Tables

Used to sort standard and hashed tables .Sorting By key :

sort [ascending|descending] [as text] [stable] .

Sorting By Different Key(s) :

sort [ascending|descending] [as text] [stable]

By [ascending|descending] [as text]

By [ascending|descending] [as text]

Number of sort fields can be a maximum of 250.

For alphabetical sorting of character columns , as text options

is used .


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Stable sort :

sort …… stable Relative sequences of lines that are unchanged by the

sort is not changed , which otherwise , does not get

preserved if sort statement is not used .

Determining Table Attributes Describe table [lines ] [occurs ] [kind

]

No. of filled lines in the table is written to variable l

, Initial size of the table is written to n and the typeof the internal table is written to K

( k=T for standard table/S for sorted table/H for HashedTable)


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Changing Lines

Using Table Key :-

Modify table from [ transporting

….]F1 ,f2 etc will be updated from wa

Changing Several Lines Using Conditions :-

Modify < itab> from transporting …. Where .


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Deleting Lines

Deleting Records Using Table Key :

Delete table from .

Delete table with table key = =

….. .Deleting Several Lines :

Delete where

Delete

Deleting Adjacent Duplicate Entries :

delete adjacent duplicates from [ comparing

….|all fields]


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Processing Loops in Internal Table

Loop at .

…. ……..

Endloop .

Loop at assigning .

… ….

Endloop .


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Example :-

loop at submat into ln .write :/ ln-matnr , ln-meins .

endloop .

Submat is an internal table , each record of which is taken into a structure ln(

which is identical to line type of the internal table)

loop at intm2 from 2 to 4 where meins = 'L' .

write :/ matdet-matnr , matdet-maktx ,

matdet-meins .

skip 1 .endloop .

(True for standard and sorted tables)


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Looping into the header line :-

Loop at intmat .

write:/ intmat-matnr , intmat-maktx .

Endloop .


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Operations For Index Tables

Applicable for internal tables maintaining index , viz.,standard and sorted tables .


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Appending LinesAppend to .

Append lines of [From ] [ to ] to .

Append to sorted by .

Insert into index .

Insert lines of into index .

Insert lines of from to into index .

When index is used , the new record is added before theline with index .


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Reading lines

Read table index .

Read table assigning index .

Deleting Lines :DELETE index .

Delete from to [where ] .

Modifying lines :Modify [from wa] [index ] [transporting c1

c2 …. [where expression]]

Write to index

Index In Loops :Loop at [from ] [to ]

. ………….. . Endloop .


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Default with sorted tables and can be adapted forsearching standard tables also .

Can be used for fetching records from standard tableusing a key other than default key.

Standard table must be sorted in ascending order bythe specified search key .The BINARY SEARCHaddition means that accessing an entry in a standardtable by its kay can be made as quickly as would beable to do in sorted table .

Searching Records Using Binary Search

READ TABLE WITH KEY = BINARYSEARCH .

READ TABLE WITH KEY = .. = binary search .


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Finding Character Strings in Internal Tables

SEARCH FOR .

Searches the internal table for the character string.

IF found :

SY-SUBRC = 0 SY-

TABIX = index of the table line in which the string wasfound.

SY-FDPOS = the offset position of the string in the table

line.

IF not found :

SY-SUBRC is set to 4.

The statement treats all table lines as type C fields, regardless of their

actual line type.


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Options :

•ABBREVIATED

Field is searched for a word containing the string in .The characters can be separated by other characters. The first

letter of the word and the string must be the same.

•STARTING AT

Searches table for , starting at line .

•ENDING AT

Searches table for , upto line .

•AND MARK

If found, all the characters in the search string (and all the

characters in between when using ABBREVIATED) are

converted to upper case.Operates for index tables only .


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CONTROL STATEMENTS

Used to react to control breaks in internal tables .Control Statements Significance

At first/endat Control for first line of internal table;

At last/endat Control for first line of internal table

At new /endat Control for beginning of a group of lines with

the same contents in the field and in the

fields left of

At end of /endat Control for end of a group of lines with the

same contents in the field and in the fieldsleft of

On change of

/endon

Perform Control break processing for a field f1

Use the SUM statement to calculate totals for the rows at control level


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Accessing Internal Tables Using FieldSymbols :

Lines of an internal table can be assigned to field symbols when

the contents of an internal table is read using READ statement or

in a LOOP . The ….ASSIGNING is used for that . The

field symbol points directly to the assigned line in memory.Field symbols allow to read and change table entries directly .

Disadvantage:-

While accessing , the contents of the key fields of sorted or

hashed tables should not be changed . The SUM statements atcontrol breaks cannot be used also .

Advantage :

No overhead for reading or modifyint internal table


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EDITOR-CALL FOR Internal Tables

Editor-call for [title ] [Display mode]

[Backup into ]

Displays the internal table itab in an editor similiar to the ABAP Editor.You can then use normal editor functions to make changes.

•The internal table itab must have the table type STANDARD TABLE,

and can contain only type C components.

The lines of the internal table can be up to 72 characters long.

The records in internal table can be changed and saved :-

•SY-SUBRC = 0 when changes are made during the session. SY-

SUBRC =2 if no changes are made .SY-SUBRC=4 means that the table

is not saved .


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See program : ysubint for demo oninternal tables

internal table udemy

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