Introduction Flashcards
Define a database
A collection of related data
Define a DBMS
Software that manages interaction and access with the database
Define a Database Application
A program that interacts with the database at some point in its execution.
Define a database system
A collection of programs that interact with the database.
Explain the File-Based system for holding data
Consisted of each department in a organisation having their own file which stored independent data relevant to that department. Each file consisted of its own records with attributes, each record modelled a real world entity.
What were the issues with a File-Based System?
Data duplication - due to each compartment having their own copy of data.
Scalability - due to data updates needing to be updated across multiple files. This increased cost and complexity.
Cross-file compatibility - due to files being developed in different languages. This made it harder to cross query.
Data dependence - Each department has their own application program which interacts with their file. If this file is changed, the application program also has to be updated (It is dependent on the file).
What was a solution to the compatability issues? Why was it not really a solution?
To create some sort of translator which converted the files into a unified language. This enabled compatibility. However, this created extra overhead, cost and complexity.
What are the 2 issues with the file-based approach that the database approach solved?
Data duplication - A unified database removed isolated files for each department, replacing it with one shared database.
Compatibility - Removal of files to a shared database mean there was no longer the needed for compatibility of files that may have been developed in different languages.
What are the 4 roles in the Database Environment?
Database Designers, Database Administrators, Users, Application Program Developers
Define the 2 types of Database Designer…
Logical Designer - Responsible for designing the logical relationships between the data in the database.
Physical Designer - Responsible for defining which structures data will be stored in throughout the database.
Define the 2 types of administrators
Data Administrator - Responsible for the implementation of the design.
Data Administrator - Responsible for defining what data is going to be stored in the database and why.
Define the 2 types of users
Naive - Unaware they’re interacting with a database.
Sophisticated - Aware they’re interacting with a database.
Define the role of the Application Program Developer
Develops programs that interact with the database.
What are 2 advantages of a file based approach?
- Each file user has complete control of the data stored in their file.
- Each file is easily modifiable
