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Fixed-length representation

  1. Uses one or more fixed-length records to represent one variable-length record.
  2. Two techniques:
  3. The reserved space method requires the selection of some maximum record length. (Figure 10.12)

    If most records are of near-maximum length this method is useful. Otherwise, space is wasted.

  4. Then the pointer method may be used (Figure 10.13). Its disadvantage is that space is wasted in successive records in a chain as non-repeating fields are still present.
  5. To overcome this last disadvantage we can split records into two blocks (See Figure 10.14) Now all records in a block have the same length, and there is no wasted space.

Osmar Zaiane
Tue Jul 7 16:00:21 PDT 1998