exchanging data

Created by

Abi

Cards (64)

What is an entity? 
An item of interest about which information is stored
What is a relational database? 
A database which recognises the differences between entities (via creating tables for each entity)
What is an attribute? 
Characteristics of the entity
What attribute links these tables together? 
DoctorID
What is a flat file?
A database that consists of a single file, which most likely bases around a single entity and it's attributes
How are flat files typically written out?
Entity1(Attribute1, Attribute2, ...)
What is a primary key? 
A unique identifier for each record in the table
What is a foreign key?
The attribute which links two tables together, it will act as a primary key in one table and a foreign in another
What is a secondary key?
A key that allows a database to be searched quickly, not unique to the field
What different relationships can databases have?
One-to-one
One-to-many
Many-to-many
Describe the one to one relationship
Each entity can only be linked to one other entity
Describe the one to many relationship
One table can be associated with many other tables
Describe the many to many relationship
One entity can be associated with many other entities and vice versa
How are one to one relationships denoted?
A single line connecting two entities
How are one to many relationships denoted?
A single line with a branch on one side
How are many to many relationships denoted?
A single line with branches on both sides
What is HTML? 
Hypertext Mark-up Language: the language that webpages are written in, allows a browser to interpret a webpage by describing the structure and order
What are the different basic HTML tags?
<html> code written between this tag is read as HTML
<body> defines the content in the main browser area
<link> used to link files (like stylesheets)
<head> defines the browser tab
<title> defines the text that appears on browser tab
<h1><h2><h3> heading styles
What are the styling/structure HTML tags? 
<p> paragraph
<img> used for images (needs parameters, is self closing)
<a> anchor tag defining hyperlink
<ol><ul> ordered and unordered lists
<li> defines an individual item list
<div> creates a division of page into separate areas which can be referred to by name
What are identifiers? 
Groups of items that can be styled
Defined with a # and must be unique to each webpage
What are classes? 
Groups of items that can be styled
Defined with a . and can be used multiple times on a webpage
What is CSS? 
Cascading Style Sheets - mark-up language that is used to describe the style of a webpage
What two ways can CSS be used? 
Internal and External
Where is internal CSS located? 
Placed inside style tags and is entered directly within the HTML document
Where is external CSS located? 
In an external CSS style sheet which is linked to the HTML
What do you add to the header when linking a stylesheet? 
<link hred= "styles.css" rel= "stylesheet" type = "text/css">
What is JavaScript? 
A programming language that adds interactivity to webpages
Is JavaScript compiled or interpreted? 
Interpreted so it can be interpreted every time the webpage is displayed
How do you change the attributes of a HTML element? 
chosenElement = document.getElementByID("example");
chosenElement.innerHTML = "Hello World";
How do you write directly to a document in JS?
document.write("Hello World");
How do you write an alert in JS?
alert("Hello World");
How do you define a function in JS? 
The same way you’d define a function in any language
What is lossy compression? 
Compression that reduces the size of a file while also removing information
What is lossless compression? 
Compression where the original file can be recovered from the compressed version
What is a network? 
Two or more computers connected with the ability to communicate
What are the two main types of network?
LAN
WAN
Describe a LAN 
Local area network:
Covers small geographical area
Owned typically by the individual
Describe a WAN 
Wide area network:
Covers large geographical area
Usually made up of many LANS
Typically owned by ISPs/telecomms
What is physical topology?
How a network is physically layed out (star and mesh)
What is a logical topology?
How data flows through a network (LAN and WAN)