relational DBMS

relational database
RDBMS
relational database management system
relational DBMS

   <database> (RDBMS - relational database management system) A
   {database} based on the {relational model} developed by
   {E.F. Codd}.  A relational database allows the definition of
   data structures, storage and retrieval operations and
   {integrity constraints}.  In such a database the data and
   relations between them are organised in {tables}.  A table is
   a collection of rows or {records} and each row in a table
   contains the same {fields}.  Certain fields may be designated
   as {keys}, which means that searches for specific values of
   that field will use indexing to speed them up.

   Where fields in two different tables take values from the same
   set, a {join} operation can be performed to select related
   records in the two tables by matching values in those fields.
   Often, but not always, the fields will have the same name in
   both tables.  For example, an "orders" table might contain
   (customer_id, product_code) pairs and a "products" table might
   contain (product_code, price) pairs so to calculate a given
   customer's bill you would sum the prices of all products
   ordered by that customer by joining on the product-code fields
   of the two tables.  This can be extended to joining multiple
   tables on multiple fields.  Because these relationships are
   only specified at retreival time, relational databases are
   classed as {dynamic database management system}.

   The first commercial RDBMS was the {Multics Relational Data
   Store}, first sold in 1978.

   {INGRES}, {Oracle}, {Sybase, Inc.}, {Microsoft Access}, and
   {Microsoft SQL Server} are well-known database products and
   companies.  Others include {PostgreSQL}, {SQL/DS}, and {RDB}.

   ["Managing Data Bases, Four Critical Factors" Michael
   M. Gorman, QED Information Sciences, Inc.].

   ["An Introduction To Database Systems" (6th ed) C. J. Date,
   Addison Wesley (an excellent source of detailed info)].

   ["An End-User's Guide to Data Base" James Martin, Prentice
   Hall (excellent place to begin learning about DBMS)].

   (2002-06-10)