Databases and SQL Flashcards
What is a database
a persistent store of organised data
What is a Table
A collection of records for a specific theme
What is a field
Categories for each piece of data in a table
What is a record
data for one object, person or place
what is a primary key
a unique identifier for each record
What is data redundancy
Where data in repeated in a table and makes it unnecessarily larger than it needs to be.
What is data inconsistency
It leads from data redundancy as the repeated data will be inconsistent and not the same.
What is a flat-file database
a database that consists of one table
What is a relational database and why is it efficient
Because it uses multiple tables which cancels out data redundancy and data inconsistency.
what does it mean that data in a database is ‘organised’
It means that the data is structured into fields, records and tables
Why might the primary key for one table, not be the same primary key in another table?
Because both tables are different and every primary key for every table needs to be unique and different
what is a foreign Key
It links a primary key from one table to the other table with the foreign key in a relational database
