ABAP INTERNAL TABLE

Attributes of Internal table:

* Line Type : Data type is normally structure.

* Key :  

                         -Standard Key (Default key)

u                         -User defined key.

* Table Type : It determines how ABAP will access individual table entries.

                      
Types :   Standard table – Indexed 

                Sorted table – Indexed

                Hashed table


Standard table : 

u

     - Have an internal linear index. 

u     - Access uses a linear search.

u     - Access either by key or index.

u     - Always non-unique.

u     - Response time for key access is proportional to number of entries in table

u     - This can filled quickly….no system checks on uniqueness of entries

Sorted table :

u     - Always saved sorted by key.

    u     - Have internal linear index.

u     -  Access either by key or index.

u     -  Table can be unique or non-unique.

u     - Response time for key access is logarithmically proportional to the no. of entries since binary search is used.

Hashed table :

u     -  No internal linear index.

u     -  Access only using key.

u     -  Response time for access is independent of no. of table entries since system accesses the table using hash algorithm.

u     -  Table key must be unique.

Populating Internal Tables:

For filling data into internal table : 

          - APPEND

          - INSERT

          - MODIFY

          - DELETE

          - MOVE

For fetching data from internal table : 

          - loop at <itab> into <wa>.     " fetch the record and holds in "wa"

            Endloop.

          -  Read.

ABAP String Manipulation :  String manipulation is the process of manipulating the values to the required format, using various manipulating commands like:

Concatenate	Split	Shift
Condense	Translate	Convert Text
Overlay	Replace	Search

* Concatenate : Combines two or more separate strings into one.

       syntax :  CONCATENATE <c1> ... <cn> INTO <c> [SEPARATED BY <s>].

Ex:  DATA: file_path(5) VALUE '/tmp/',
        name(8)     VALUE 'MATERIAL',
        ext(4) VALUE '.txt',
        file_name(50).
  CONCATENATE  file_path  name  '_'   sy-datum  '_'   sy-uzeit  ext     INTO file_name.
  Write : 'File Name is :', File_name.

  Out Put:   file_name has value “/tmp/MATERIAL_20060222_064430.txt”.


* Split : Split a character string into two or more smaller strings.
       syntax : SPLIT <c> AT <del> INTO <c1> ... <cn>.

Ex:          DATA:  file_name(30) TYPE C VALUE 'tmp/MATERIAL.txt', 

                directory(10)   TYPE C,
                name(12)         TYPE C,
                delimiter(1)     VALUE '/'.
                SPLIT file_name AT delimiter INTO directory name.
                 Write :  'directory : ' ,  directory .

  Out Put: Now directory contains “tmp” and name contains “MATERIAL.txt”.


* Shift : Shift the contents of a field, character by character.
       syntax : SHIFT <c> [BY <n> PLACES] [<LEFT/RIGHT/CIRCULAR>].
Ex:       DATA v_cost(10) TYPE c VALUE ‘345.98-’.

              SHIFT v_cost BY 1 PLACES RIGHT CIRCULAR.    

 Out Put: Now v_cost = “-   345.98”.

* Condense : Deletes redundant spaces from a string.

       syntax : CONDENSE <c> [NO-GAPS].

Ex:       DATA var(10) TYPE c VALUE ' HELLO '.
            CONDENSE var.
            WRITE : var.  

  Out Put:  Now Var will holds the value "HELLO" by deleting initial and ending Blank Spaces.

* Translate : Converts characters into upper or lower case, or uses substitution rules to convert all occurrences of one character to another character.

       syntax :  TRANSLATE <c> TO UPPER CASE/LOWER CASE. 

                      TRANSLATE <c> USING <r>.

Ex:       DATA: letters(20) TYPE C VALUE 'abcabcabcXabc',
                        change(15) TYPE C VALUE 'aXbaYBabZacZB'.
            TRANSLATE letters USING change.
            WRITE : letters.

 Out Put:  letters now contains 'XaZXaZXaZXXaZ'.

* Convert Text : Converts strings into a format that can be sorted alphabetically.

       syntax :  CONVERT TEXT <c> INTO SORTABLE CODE <sc>.

field <c> must be of type C and the field <sc> must be of type X with a minimum size of 16 times the size of <c>. 

Ex:       DATA: Var(5) TYPE C VALUE 'Hello',

                         Con_text TYPE xstring.
              CONVERT TEXT var INTO SORTABLE CODE Con_txt.
              WRITE : Con_text.

 Out Put:  Now Con_text will holds the value "342E3C3C420109018F08".

* Overlay : Overlays one string with another.

       syntax :   OVERLAY <c1> WITH <c2>.

Ex:       DATA: c1(4) VALUE 'ABC',
                         c2(4) VALUE 'XVYZ'.
            OVERLAY c1 WITH c2 ONLY 'B'.
            WRITE c1.
 Out Put:  Now C1 holds the value "AVC".

ABAP Data Types

Difference between Type & Like:

* Type : refers to the user defined data types.

Ex:     TYPES : Var1 TYPE i.

        TYPES : Var2 TYPE Var1.

* LIKE  : refers to existing data type of data object.

Ex:     Data : Var1 TYPE i.
        Data : Var2 Like Var1.
Difference Between F & P Data Type:
Float Data Type :  It cannot be declared in Parameters.

Packed Data  Type :  It can be declared in Parameters.