1.3.2 Databases Flashcards
(14 cards)
1
Q
List common data types stored in databases
A
- Text
- Currency
- Date
- Time
- Integer
- Real
- Boolean
2
Q
What is a primary key?
A
- A unique identifier that is used to identify a specific record in a table.
3
Q
What is a composite key?
A
- A unique identifier comprised of two or more values
- These values may not be unique themselves but they make up a unique combination in the table.
4
Q
What is a foreign key?
A
- A primary key that is stored in another in a field of another table which is used to make links between tables.
5
Q
What is a table comprised of?
A
- Fields
- Records
6
Q
How can data be collected for a database?
A
- User inputs through forms which are given to automated queries.
- Manual entries called ad hoc queries
7
Q
What is data redundancy?
A
- Duplication of data or unnecessary data is stored in a database
8
Q
What is a flat file database?
A
- All data is stored in a single table
9
Q
What is a relational database?
A
- Data in the database is stored across multiple tables which are linked using foreign keys.
10
Q
What is data consistency?
A
- Data can only be added or changed a query follows a specific set of predefined rules such as constraints or triggers.
11
Q
What is logical data independence?
A
- The ability to adapt logical aspects of a database without affecting the database applications.
- e.g adding/removing entities, changing or removing relationships.
12
Q
What is physical data independence?
A
- The ability to adapt physical aspects of a database without affecting the database applications.
- e.g. changing the device the database is running on.
13
Q
What is data integrity?
A
- Ensuring that the accuracy, completeness and consistency of the data is reliable.
14
Q
What is referential integrity?
A
- Ensuring that if a foreign key is added to a foreign key field, there is a corresponding primary key in the table that the foreign key field is linking to.
