Data Structure and Terminology
In the relational model, a database
is a collection of relational tables. A
relational table is a flat file composed
of a set of named columns and an
arbitrary number of unnamed rows. The
columns of the tables contain
information about the table. The rows of
the table represent occurrences of the
"thing" represented by the table. A data
value is stored in the intersection of a
row and column. Each named column has a
domain, which is the set of values that
may appear in that column. Figure 1
shows the relational tables for a simple
bibliographic database that stores
information about book title, authors,
and publishers.
Figure 1
There are alternate names used to
describe relational tables. Some manuals
use the terms tables, fields, and
records to describe relational tables,
columns, and rows, respectively. The
formal literature tends to use the
mathematical terms, relations,
attributes, and tuples. Figure 2
summarizes these naming conventions.
Figure 2:
Terminology
| In This Document |
Formal Terms |
Many Database Manuals |
|---|
| Relational Table |
Relation |
Table |
| Column |
Attribute |
Field |
| Row |
Tuple |
Record |
Using simplified relational Notation,
relational tables can be expressed concisely by
eliminating the sample data and showing just the
table name and the column names. |
Data Modeling
