Fundementals of Databases Flashcards
What does a record in a database indicate?
a row
What does a field in a database indicate?
A column
What is a falt file database?
A single table that stores all of the data held within that database
What is an advantage of a flat file database?
- Easy to setup
- can be made in software that many people can access such as a spreadsheet (excel)
What are limitations to a flat file database?
- ‘data duplication/redundancy’ - repeating data unnecessarily
- due to data duplication, flat file databases require much more storage
What is a relational database?
A database that consists of a number of linked tables in which each record usually records about a particular entity
What does each linked table in a relational database NEED to have?
A primary key
What is the main benefit of a relational database?
data does not have to be duplicated - this means it requires less storage as well as reducing the risk of mistakes that can happen when repeatedly inputting data
Define a primary key
a field/combination of fields in a table which is unique and enables you to identify every record in that table
What are the 2 types of primary keys?
- Simple
- Compound/composite
Define a simple primary key:
made up of a single field only
Define a compound/composite primary key
combines more than 1 field to make a unique value
What is a foreign key?
used to link tables together and create a relationship - it is the field in one table that is used to link to the primary key in another table
What is an orphan record?
A record that is not linked to any table where it should be
What is normalisation?
a technique for designing relational database tables to minimise duplication of information and to therefore safeguard against certain types of logical/structural problems