PPT Slide

We have mostly illustrated storage and retrieval with simple entities such

as ints or strings. Then the value of an object and its unique identifier

are one and the same. But in practice what is stored and retrieved

are objects such as personnel records, descriptions of regions in

space, items for sale in a catalog, forms defining a sale from a

catalog, dictionaries, etc. We typically use some subset of the values

of an object as a key.

Key - A value or values (an object type) which can be used to locate the storage

location of another object or collection of values.

1. The unique identifier of an object may be used as its key or

a key may be derived from the unique identifier.

2. We speak of “searching for a key.” to find the location of the object

to which it refers.

3. But the index of a location in an array or vector is a location which

can be computed.

What do we store and retrieve?