Cunning Schemes
An overview of a database structure using methods such as an ER diagram. It is independent of any particular DBMS
Describe what is meant by a logical schema
It allows the user to enter criteria, searches for matching data and displays results to the user
Describe the purpose of a query processor in a DBMS.
No repeating attributes or groups; data is atomic
What is First Normal Form?
One or more attributes / fields that could be used to uniquely identify a row
State what is meant by a candidate key in a relational database
All the data is required, otherwise the text will be corrupted
Why should you not use lossy compression on text files
It stores metadata about the database
Describe a data dictionary
It must have a compound primary key, and some attributes are only dependent on one part of that key
How can a database table break second normal form?
An attribute or field in one table that is linked to a primary key in another table.
What is a foreign key?
It redirects a user to a false website
What is pharming?
They reduce data redundancy, inconsistency and program-data dependency. Complex queries are easier and different views can be provided
Why are relational databases better than flat file databases?
A case where one attribute depends on another attribute that is not the primary key.
What is a transitive dependency?
A row of data in a table about one instance of an object.
What is a tuple?
To store flags which are set by events, or from the results of arithmetic and logic operations, and interrupt flags
What is the purpose of the Status Register?
A software tool that allows the user to create items such as tables, forms and reports
What is a Developer Interface?
A. Remove any repeating attributes or groups
B. Remove any partial key dependencies
C. Remove any non-key dependencies
How do you get from 0 Normal Form to 3rd Normal Form?
The address / memory location of the next instruction to be fetched
What does the Program Counter contain?
It makes sure that data are consistent, up-to-date, and that every foreign key has a corresponding primary key.
What is Referential Integrity?
A signal from a device or process, seeking the attention of the processor
What is an interrupt?