DATA - HEADER LINE
... WITH HEADER LINE ...
This addition of the statements DATA TABLE
DATA RANGE OF,
and the obsolete statement
DATA OCCURS (which is not allowed in classes) declares a further data object alongside the internal table, known as the
header line. This object
has exactly the same name as the internal table and has the row type of the internal table as its data
type. A header line cannot be declared for internal tables with a table-like row type. This is possible for structured row types with table-like components, however.
If the name of an internal table
itab is specified in an operand position of an ABAP statement, the statement determines whether the
table body or header line
is used. As a rule, all table-specific statements such as
LOOP use the internal table, whereas all other statements use the header line. Exceptions to this rule are listed under
Internal Tables with Header Line.
To address the table body instead of the header line in statements,
 can be appended to the table name:
... itab ...
For internal tables without a header line, the table body is always used. An internal table with a header line cannot be a component of a structure or a row of another internal table.
- These statements for processing individual table rows have obsolete short forms that use the header line as a work area implicitly. These short forms are allowed only outside of ABAP Objects.
If the name
primary_keyis explicitly specified or a secondary key is defined when the primary key is being defined, the addition
WITH HEADER LINEcan no longer be specified, either inside or outside of classes.