Logical data logical network design pdf represent the abstract structure of a domain of information. They are often diagrammatic in nature and are most typically used in business processes that seek to capture things of importance to an organization and how they relate to one another. Even so, since the logical data model anticipates implementation on a specific computing system, the content of the logical data model is adjusted to achieve certain efficiencies.
While the two concepts are closely related, and have overlapping goals, a domain model is more focused on capturing the concepts in the problem domain rather than the structure of the data associated with that domain. This is not the only way to look at data models, but it is a useful way, particularly when comparing models”. A logical data model is sometimes incorrectly called a physical data model, which is not what the ANSI people had in mind. The physical design of a database involves deep use of particular database management technology.
That is the domain of the physical model. Conceptual, logical and physical data models are very different in their objectives, goals and content. Includes primary keys and indices for fast data access. May be de-normalized to meet performance requirements based on the nature of the database.
De-normalization is common in Datawarehouses. By George Tillmann, DBMS, June 1995. This page was last edited on 3 December 2017, at 18:23. Diagram of different network topologies. There are two main types of topology. The names used – such as ring or star – are only rough descriptions. The computers on a home network can be arranged in a circle but it does not necessarily mean that it represents a ring network.