1.3.1 Databases Flashcards
What is entity relationship modelling?
A method of abstractly describing the data tables and the relationships between them visually.
Define Flat File
A single table data structure used to store all data.
Define foreign key
A linking attribute that joins two tables in a relational database by being a primary key in one and being a foreign key in another.
What is the normalisation of data bases?
Optimally designing data tables by reducing data redundancy and repetition by converting them into normal forms.
Define primary key
A unique identifier identifying each record in a table.
Define redundancy
The unnecessary repetition of a field in multiple tables.
How should databases have redundancy?
In the form of identical copies if part of the database gets lost and needs to be recovered.
What can ER modelling be used to do?
They can be used to reduce redundancy and construct a relational database.
What is a relational database?
A database where separate tables are made for each entity, and relationships between entities are represented by foreign keys.
How are primary and foreign keys identified?
Primary is underlined
Foreign use asterisks.
