3. Technical Optimisation, Goal

Scope Logical Design Technical Optimisation Implementation

1. Scope

2. Logical Design

3. Technical Optimisation

4. Implementation

The logical design is a working model. You could implement the design as is, and it would work, albeit a bit slow.

Technical optimisation (physical database design) focusses on

Efficiency
Techical optimisation makes sure that the most important functions perform good.
Simplicity
A fully logical model can be troublesome to work with. For example SQL queries can be quite complex on a 100% logical database.
The logical design is guided by rules. At technical optimisation it's comes down to creativity, inventivity and technical skills.