Database Management Flashcards
Section 8
Database
A repository of information and a collection of tables that are related to each other
What are the rows and columns of the table called
rows are data records and columns are data fields
What is attribute and which aspect of the table stores it
These are the facts known about an entity (fields)
What is an entity and which aspect of the table stores it
This is anything you want to store information about (records)
What is a record
Gives information about a single entity (sometimes called a tuple)
What is a field
Stored a single piece of information
What are three characteristics of a field
Has a name, has a size, has a data type
What are the three main types of fields
Numeric, Text and Logical
State 4 reasons why data bases are useful
Standardisation, Fast retrieval, Large Size, Multiple views
List 6 types of keys
Primary, Alternate, Composite, Candidate, Secondary, Foreign
Describe the foreign key
Used to link different tables in a relational database. A column in one database that references the primary key of another table
Primary key
Often a code number: Used to uniquely identify every record in the database
Alternate key
keys that could be used for the same purpose
A table should…
hold information about only 1 type of entity
Each piece of information…
should be stored only once in the database
Secondary Key
A column or a set of columns within a table that can be used to search and retrieve data based on criteria other than the primary key
Candidate Key
A set of one or more columns that can uniquely identify each row in a table
