databases Flashcards
What is a database?
A way of organising data/information so that it can be accessed easily.
Why are databases useful?
They store large amounts of data, hold data in an organised way, make it faster to carry out searches, are freely available, and interact with different systems.
What is a Flat File database?
The simplest database, consisting of a single table.
What are attributes in a database?
Column names and the data they contain. Data is called fields.
What are records in a database?
Refers to one entry (column) in the table, also known as an instance.
What are the data types in a database?
Varchar, Number, Date.
What is Varchar?
Variable Character, like a string in Python, a series of numbers, letters and other characters.
What is a Number data type?
A number that can be used in calculations.
What is a Date data type?
Typically date/month/year, but can also be an integer value based on the number of days since 31/12/1899.
What is CSV?
Comma Separated Value, a file type used to store flat file databases.
What are Relational Databases?
Databases that store and provide access to data points that are related to one another.
What are the problems with single data tables?
Duplicate data, wasted time replacing duplicate data, wasted storage space, and hard to extract specific data.
What is a Primary Key?
A unique identifier generated to reference records.
What is a Foreign Key?
An attribute that is created to link different tables.
What is an ERD?
Entity Relationship Diagram, used to visualise the relationship between entities (tables).
