Working with database tables and internal tables

* Declaration of a work area for a Dictionary table
TABLES CUSTOMERS.
* Internal table used as snapshot of the database table
DATA ALL_CUSTOMERS LIKE CUSTOMERS OCCURS 100
WITH HEADER LINE.
* Reading the entries of the database table into an internal table
SELECT * FROM CUSTOMERS INTO TABLE ALL_CUSTOMERS.
* Displaying each line of an internal table
LOOP AT ALL_CUSTOMERS.
WRITE: / ALL_CUSTOMERS-NAME.
ENDLOOP.
*&---------------------------------------------------------------------*
* 1. Elementary types
Other Approach to define data type
DATA: CUSTOMER_NAME_1(25) TYPE C,
VENDOR_NAME_1(25) TYPE C.
* 2. Reference to an existing field
DATA: CUSTOMER_NAME_2(25) TYPE C,
VENDOR_NAME_2 LIKE CUSTOMER_NAME_2.
* 3. Reference to a non-elementary type
TYPES T_NAME(25) TYPE C.
DATA: CUSTOMER_NAME_3 TYPE T_NAME,
VENDOR_NAME_3 TYPE T_NAME.