Re: Network databases
Date: 11 Jan 2005 07:06:40 -0800
Message-ID: <1105456000.624863.303900_at_f14g2000cwb.googlegroups.com>
If my memory is correct a networked database could only follow
predefined paths to the data. Nodes (chunk of data) were chained to
other nodes using pointers and these prebuilt pointer chains were the
only paths through the data.
A relational database on the other hand supports accessing data in a
more flexible manner and does not use predefined pointers to the data
elements. In theory any column can be used to join to any other column
in another table. Obviously you would only do this when the data in
question was actually the same data values and for performance reasons
you would probably add indexes on these columns. But the point being a
user can declare any relation that makes business sense at run time
rather than at object definition time.
I hope this is clean enough. I believe that CA still supports a legacy
network database product. The methods being discussed in the OO world
may include "fixes" for some of the problems on network db designs of
the past. For certain types of applications a network design would be
very fast as only one IO would be required for each node.
HTH -- Mark D Powell --