Uses one or more fixed-length records to represent one variable-length record.
Two techniques:
Reserved space - uses fixed-length records large enough to
accommodate the largest variable-length record.
(Unused space filled with end-of-record symbol.)
Pointers - represent by a list of fixed-length records,
chained together.
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.
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.
To overcome this last disadvantage we can split records into two blocks
(See Figure 10.14)
Anchor block - contains first records of a chain
Overflow block - contains records other than first in the chain.
Now all records in a block have the same length, and there is no wasted space.
