Multi-dimensional database model (sometimes called the
"Post-relational" "Multi-valued" or
"Pick" model) offers significant advantages
over the traditional "flat" or
This is the
area in which the two models differ the most.
multi-dimensional databases allow multiple (or even
no) occurrences of any data field. This allows them
to mirror the real world more closely.
personnel file. The records, or "rows", in
this file may include a telephone number field. An
employee may have one telephone number, many numbers
or no telephone number at all. And the telephone
numbers may vary in length.
If you were
using a relational database you'd have to provide
space in each row for an arbitrary number of
occurrences of the telephone number field, and each
occurrence would be of a fixed, arbitrary length.
And if, at a
later stage, you were to increase the number of
occurrences, or to change the length of one of these
fields you'd probably have to modify every program
that accessed that file.
But if you
were using a multi-dimensional database (such as
UniVerse) the system will automatically allow as many
occurrences of that field as each record (row)
requires, and allow each occurrence to be as long as
it needs to be.
records (rows) are considered dynamic both in terms
of length and in terms of the number of fields.
programming languages supplied with the DBMS include
functions to handle variable length records and
multiple values - thus reducing program maintenance
if a record layout is amended.
efficient use of disk resources
above example: In the traditional scheme of things
you'd have to provide for n
occurrences of that field, and fix the length of the
And that space
the field length) is used for each row whether the
fields contain any data or not.
But in the
multi-dimensional scenario all that is written to
disk is the actual data (with no padding) and a
single field delimiter - no unnecessary space is
occupied. This only saves a few bytes per record,
that's true. But this saving becomes significant in a
(or "row") in a file (or "table")
is identified by a unique key field. And all records
are directly accessible by this key.
need to parse the entire table. If you have the key
you can efficiently and directly access the record
that you want.
And access via
this primary key does not require any indexing -
although this facility is available to provide
alternate record keys.
This family of
DBMS uses a special algorithm for encoding dates for
internal storage. This results in dates that, when
stored on disk, occupy less space than dates stored
in the MMDDYY (or similar) format; yet can be
converted into various formats (23-01-97; 23 January
1997, 01/12/1997 etc.) for display. This date
handling scheme also greatly reduces the problems
associated with working with dates that fall within
ad hoc database querying
DBMS offer an easy to use, English-like language for
querying and reporting from the database.
useful feature is the "select list". In
"relational" terms a select list is a list
of rows from a table that meet user specified
criteria. Once the list is established subsequent
processing or queries are carried out on the selected
of open standards
DBMS now integrate with most of the de facto
"open" standards and programming tools such
as ANSI SQL, ODBC, and Visual Basic. They thus
interact easily with modern Windows based products.
DBMS are available for Windows NT and all major
commercial UNIX variants. And applications and data
are easily ported across hardware and software
multi-dimensional system will move and grow with your