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C H A P T E R 1 1
Data Storage and Retrieval
About Data Storage on Newton Devices
11-17
Figure 11-5
Cursor presents discontiguous index key values contiguously
Entries
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An entry is a special kind of frame that resides in a soup. Valid entries can be
created only by system-supplied methods provided for this purpose--you cannot
create an entry by creating a frame having certain slots and values. The entry that
these methods create consists of the frame presented to the entry-creation method,
along with copies of any data structures the frame references, as well as copies of
any data structures those structures reference, and so on. An exception to this rule
is that
_proto
slots are not saved in soup entries. Circular references within an
entry are allowed.
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4
6
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beginKey
Indexed entries
Eliminate more
entries
Valid entries
in black
Valid entries as
presented by
cursor
Select subrange
of valid entries
endExclKey
indexValidTest: func (key)
begin
(key MOD 2 = 0)
end
subrange of index key values
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