Chapter 10 Database and Data Modelling
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What does file-based approach mean?
File-based approach means to gather data into one file.
What are the disadvantages of file-based approach?
In file-based approach there is data redundancy, lack of data privacy and lack of data validation.
What does data dependency concerns mean?
Data dependency concerns is when a file is changed for example an extra column is added and the programs accessing this file have to be re-written so that they wouldn’t get the wrong data.
What is a database approach?
The database approach is an implementation according to the rules of a theoretical model
What is the name of the theoretical models name used in the database approach?
The ANSI three-level architecture.
Which are the three levels in the ANSI three-level architecture?
Internal level - Accommodates any changes that might be needed in the storage medium Conceptual level - A person who uses the DBMS to customize the database to suit user and programmer requirements External level
What is the external level?
The external level is the level from which most of the users control the database
What is a relational?
A relational is a special type of table which is used to show the entities functions for example the date of production of a car.