Chapter 5 Flashcards
What is a conceptual model?
The logical structure of the entire database.
What is another term for conceptual schema?
Logical schema.
What does data independence refer to?
The immunity of user applications to changes made in the definition and organization of data.
What is a data model?
A collection of concepts or notations for describing data, data relationships, data semantics, and data constraints.
What is data modelling?
The first step in the process of database design.
What does database logical design define?
Defines a database in a data model of a specific database management system.
What does database physical design define?
Defines the internal database storage structure, file organization, or indexing techniques.
What is an entity relationship diagram (ERD)?
A data model describing the database showing tables, attributes, and relationships.
What does the external model represent?
The user’s view of the database.
What is the external schema?
User view.
What is the internal model?
A representation of the database as seen by the DBMS.
What is logical data independence?
The ability to change the logical schema without changing the external schema.
What is logical design?
Where you create all the tables, constraints, keys, rules, etc.
What is a logical schema?
A conceptual design of the database done on paper or a whiteboard, much like architectural drawings for a house.
What does an operating system (OS) do?
Manages the physical level of the physical model.
What is physical data independence?
The immunity of the internal model to changes in the physical model.
What is a physical model?
The physical representation of the database.
What is a schema?
An overall description of a database.
