Database(DB) – DB environment summaries (P2)

2. Relational Data Model:

- What is Relational Data Model?

>> It aims to get how data make their relationship by representing the logically structure within tables (relations)

- What are the objectives of Relational Data Model?

>> Allowing high degree of data independence.
>> Giving the substancial (important, real) grounds for dealing with any problems within database.
>> Enable expandsion of set-oriented data.

- Relational Data Structure: see this picture below

A whole table with colums & rows = Relation
An Attribute = A column’s name
A Tuple = A row
A Domain = all the allowable values for 1 or more attributes

Degree = the number of attribute(s)
Cardinality = the number of tuple(s)

Relational Database = collection of Relations with distince relation names.

~ by vanganhxinh on February 29, 2008.