Types of Internal table Declarations in ABAP

 Types of Internal table Declarations in ABAP

Three  types of internal table available in SAP ABAP.

1. Standard tables are managed system-internally by a logical index. New rows are either attached to the table or added at certain positions. The table key or the index identify individual rows.

2. Sorted tables are managed by a logical index (like standard tables). The entries are listed in ascending order according to table key.

3. Hashed tables are managed by a hash algorithm. There is no logical index. The entries are not ordered in the memory. The position of a row is calculated by specifying a key using a hash function.

Declarations : - 

Types: BEGIN OF ty_mara,
       matnr TYPE mara-matnr,  " material
       ersda TYPE mara-ersda,  " created on
       ernam TYPE mara-ernam,  " created by
       mtart TYPE mara-mtart,  " material type
      end of ty_mara.

data: It_mara TYPE STANDARD TABLE OF ty_mara.                        " standard internal table
data: it_mara2 TYPE SORTED TABLE OF ty_mara WITH UNIQUE key matnr.   " sorted internal table
data: it_mara3 TYPE HASHED TABLE OF ty_mara WITH UNIQUE key matnr.   " hashed table