Logical Data Modeling - Attribute
Table of Contents
1 - About
An attribute is a property or characteristic of a primary element (entity, relationship)
For example, a color attribute could have been modeled also as an entity with several attributes (warm, cold, …)
The values for each attribute are defined in terms of properties.
An attribute is known as a:
2 - Articles Related
3 - Functionality
The value of an attribute may have one of this functionalities:
4 - Properties
Each attribute are defined in terms of properties (metadata attributes):
- Name:
- the name of the attribute may contain a prefix of its element
- Description
- Attribute Source Category:
- Designed
- Data type (what class of data can be stored in that attribute)
- Length and/or precision
- Domain: enumeration, range of permitted, legal values / Format patterns (what values an attribute can legitimately take on)
- Default value or algorithm (what default value are recorded if not specified by the user)
- Optionality: Mandatory or optional
- analytical property - descriptive or measure
4.1 - Attribute Source Categories
4.1.1 - Basic
An Attribute Value that cannot be deduced or calculated. Examples:
- Student name
- Birthday
4.1.2 - Derived / Calculated
4.1.3 - Designed
The Attribute is created to overcome the system constraints. The value of a Designed Attribute does not change. Attribute does not change.
Examples:
- Student ID,
- Course number.