Relational Database Model: Keys, Dependencies, and Table Structure
What is an example of a functional dependency?
(STU_NUM, STU_LNAME) → STU_GPA
What is a foreign key (FK)?
A primary key from another table used to implement the relationship between two tables
What is the significance of the primary key in a relational database?
It ensures that each row in a table is uniquely identifiable
What does the relational database model enable?
Logical representation of data and its relationships
Is the order of rows and columns relevant to the DBMS?
No, the order is irrelevant
In the example STU_NUM → STU_LNAME, what does STU_NUM represent?
The determinant that determines the value of STU_LNAME
What is the attribute domain in a relational table?
The specific range of values that each column can have
What does functional dependence mean?
The value of one or more attributes determines the value of one or more other attributes
What is the purpose of keys in a relational database?
To ensure each row is uniquely identifiable and to establish relationships among tables
What is full functional dependence?
When the entire collection of attributes in the determinant is necessary for the relationship
Can a determinant contain unnecessary attributes for the relationship?
Yes, it can contain attributes that are not necessary
What must each table have to uniquely identify each row?
A primary key or a combination of attributes
What is represented by the intersection of a row and a column in a table?
A single data value
What does each row in a relational table represent?
A single entity occurrence within the entity set
What is a 'relation' in the context of a relational database?
A table that is a 2-dimensional structure composed of columns and rows
What does each column in a relational table represent?
An attribute with a distinct name
Who is the creator of the relational model?
E. F. Codd
What is a primary key (PK)?
An attribute or combination of attributes that uniquely identifies any given row
What is a determinant in functional dependence?
An attribute whose value determines another attribute
What is a dependent attribute?
An attribute whose value is determined by another attribute
What is the relationship between STU_NUM and STU_GPA?
STU_NUM determines STU_GPA
