Diff b/w occurs 0 and 1

Question

hi,
what is the difference b/w occurs 0 and occurs 1?
and what is the significance of begin of?

Answer 1

The number <N> indicate how many lines has to have the table in initialization time: i.e. when the program is loaded in memory, the space for the table depends on the initialization numbers of the records.
AT run time if the table needs more space, this'll automatically be enhanced.
But If you know your table can have a certain numbers of records, you can indicate it in the defination, what'll improve the performance:
all the space the table needs is taken at the beginin, so it doesn't need to enhance the space at run time.
When this initial area is full, the system makes twice as much extra space available up to a limit of 8KB. Further memory areas of 12KB each are then allocated.
You can usually leave it to the system to work out the initial memory requirement. The first time you fill the table, little memory is used. The space occupied, depending on the line width, is 16 <= <n> <= 100.
It only makes sense to specify a concrete value of <n> if you can specify a precise number of table entries when you create the table and need to allocate exactly that amount of memory (exception: Appending table lines to ranked lists). This can be particularly important for deep-structured internal tables where the inner table only has a few entries (less than 5, for example).
To avoid excessive requests for memory, large values of <n> are treated as follows: The largest possible value of <n> is 8KB divided by the length of the line. If you specify a larger value of <n>, the system calculates a new value so that n times the line width is around 12KB."