ISDD Flashcards
Describe the structure of a database?
Databases contain tables, these tables contain records which is all the data stored about one object, the records contain fields which is a single piece of information on the object.
What are the advantages of a relational database?
avoid unnecessary duplication of data
tables are linked so data only needs to be changed once
What are the purpose of primary, surrogate, foreign and compound keys?
Primary key is a unique identifier for a record
A surrogate key is a field in a table which has been created to ensure a unique field exists
A foreign key is used to link fields together in different databases
A compound key combines more than one field in order to make a unique value
What are the purpose of tables, forms and reports?
tables display large amounts of data on the one screen
A form is graphical and displays one record at a time
A report is used to arrange data into an easy to read or print format
What is meant by a relationship in a database?
a relationship is when one or more entity is associated with each other
What is a calculated field?
A calculated field is one which is created using a query which calculates a result from one or more existing fields
How can websites be structured?
Websites can be structured in a linear format or in a hierarchical format
What will all websites contain?
Head, title and body
What do style sheets allow us to do?
Style sheets allow us to separate the look and feel of a web page from its content and structure.
Make sure pages on a web page are consistent in appearance
How can web pages be structured into different sections?
Using , and
What does CSS stand for and what is it used for?
Cascading style sheets
is a standard way of implementing style sheets
What does CSS consist of?
Consists of rules they are made up of a selector and a group of attributes called the declaration
Where is metadata found?
Metadata is found in the head section of a webpage
What is Metadata used for?
Metadata is used to give information about a webpage
What are static web pages and what is a dynamic web page?
A static web page does not change every time they are viewed
A dynamic web page contains information which will change each time the page is loaded
What is an interactive web page?
An interactive web page is one that requires the user to click on buttons or other elements in order to interact
What is a database driven website?
A database driven website is a dynamic web page which allows users to search through stored information.
What is a standard file format?
A standard file format is one which will open and display correctly on all platforms?
Why is compression necessary and what its advantages?
Media files can be very large.
allows more files to be stored on to backing storage
files will be faster to transmit and download over the internet
What is compressions job?
Compression is used to reduce the size of files
Explain the difference between lossless and lossy compression?
lossless reduces file size but does not lose any information. lossy reduces file size but loses information
How can the size of sound files be reduced?
Croppping
Lowering sampling depth
lowering sampling frequency
How can the size of graphics files be reduced?
Cropping
lowering resolution
changing colour depth
How can the size of video files be reduced?
Shorten length
altering resolution
reducing the frame rate