difference between with and without header line of internal table
can you explain
1) The difference between
whih header line and with out heater line of internal table.
a) Data : itab like mara occurs 0 with header line.
b) Data: itab like mara occurs 0.
2)work area / field string and internal table
which one is prefarable for good performance any why ?
Please give the detailed explanation with example code.
Thanks in advance