Topic 1a : Structures and Links (Databases) Flashcards
A database is a
structured collection of information on people or things.
Databases are made up of;
fields, records and files
A field stores
one piece of data about a person or an object.E.G. telephone number
A record stores
The data on one person or object in the file. E.G. Information on one pupil in a school
A file is
A collection of Records
A flat file database is a
database structure which has only one table containing all the fields and the data they hold
A relational database
has more than one table.
1 advantage of a relational database is
that is ensures data is only entered and stored once
2nd advantage of a relational database is that it
removes the possibility of data duplication and inconsistency
3rd advantage of relational database is
All tables containing the data are linked
Person’s name or address is an example of what field type ?
Text
Someone’s annual salary is an example of what field type?
Number
Someone’s D.O.B. is an example of what field type?
Date
An appointment time is an example of what field type?
Time
An image of the pupil in school records is an example of what field type?
Graphics
Monthly salary = annual salary/12 is an example of what field type
Calculated
A field containing a link to files on your computer or a network or location on the internet is an example of what field type?
Link
A field designed to store a value of 1 or 0, or with a yes/no option is an example of what field type?
Boolean
A key field does what?
Uniquely identifies each record in the database e.g. Scottish Candidate Number
A foreign key does what?
Sets up links between 2 tables in a database. It is a field that will appear in both table.
Validation is when you
check to make sure the correct type of data is being entered into a field
Field Length checks that
the correct number of either numbers or characters have been entered into a field.
Range checks that the number entered in a field
falls between a minimum and maximum value.