Databases (Cambridge (CIE) O Level Computer Science)
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What is a database?
A database is an organised collection of data
Define the term field.
A field is one piece of information relating to one person, item or object.
What is a record in a database?
A record is a collection of fields relating to one person, item or object.
True or False?
A field is represented by a row in a database table.
False.
A field is represented by a column in a database table.
Define validation rule.
A validation rule controls what data can be entered into a field.
What is a length check?
A length check is a validation that checks the number of characters entered into a field.
True or False?
A presence check ensures a field cannot be left blank.
True.
A presence check ensures a field cannot be left blank.
What is a data type?
A data type is the type of data that can be held in a field and is defined when designing a table.
State two examples of common data types.
Examples of common data types are:
Numeric,
Character/string,
Date/time,
Boolean.
What is the advantage of using a database over a text file for large amounts of data?
A database allows easy storage, retrieval, and management of information for large amounts of data.
What is a primary key?
A primary key is a unique field that can be used to identify a record in a table.
True or False?
A primary key must be numeric.
False.
A primary key can be any data type, as long as it uniquely identifies each record.
Define foreign key.
A foreign key is a field in a table that refers to the primary key in another table.
What is the purpose of a foreign key?
A foreign key is used to link tables and create relationships.
True or False?
Every table must have a primary key.
True.
Every table must have a primary key to uniquely identify each record
What field would make a good primary key?
CustomerID
FirstName
LastName
DOB
PhoneNum
001
Andrea
Bycroft
05031976
0746762883
002
Melissa
Langler
22012001
0756372892
003
Amy
George
22111988
074637
CustomerID
Define record in database terminology.
A record is a group of related fields, representing one data entry.
What is a field in database terminology?
A field is a single piece of data in a record.
True or False?
The primary key can be composed of multiple fields.
True.
The primary key can be composed of multiple fields, known as a composite key.
State an example of a typical primary key in a school database.
A typical primary key in a school database would be:
Student_ID