123 School Work

Logical Design and Physical Network Design

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  Logical Design
  A logical design is a conceptual, abstract design. At this stage, the system analysts do not deal with the physical implementation details; they are only concerned with defining the types of information that the organization needs to access through the networks (Hoffer, George, and Valacich, 2002). The process of logical design involves arranging data into a series of logical relationships, which are referred as entities and attributes. An entity represents information about a place, object, events, and concepts. In relational databases, an entity often maps to a table. An attribute is a component of an entity and helps define the uniqueness of the entity. In relational databases, an attribute maps to a column. One output of the logical design is a set of entities and attributes corresponding to fact tables and dimension tables. Another output of mapping is operational data from the source into subject-oriented information in a target data warehouse schema. In this approach, the system analysts identify business subjects or fields of data, define relationships between business subjects, and name the attributes for each subject...