1. IS2803 Developing Multimedia Applications for Business (Part 2) Lecture 1: Introduction to IS2803 Rob Gleasure R.Gleasure@ucc.ie www.robgleasure.com

2. IS2803 Today’s lecture  Discussion of IS2803  Continuous assessment  A note on databases

3. IS2803 What are we covering?  PHP  SQL  XML  Semi-structured and unstructured data

4. Continuous Assessment Date tbd TheBigScreen website was a hit! The company that commissioned you to build it is so excited by the new business it is generating that they have hired you to expand the existing functionality to allow new reviews to be entered by users The new functionality concerns  The creation of user accounts  The addition and display of user reviews

5. Continuous Assessment Login functionality You have been asked to add login/register functionality to the site, so that registered users can enter reviews.  The company have requested this information be stored in an MS Access database, as this is most compatible with their existing software.  Each user record must contain: A unique username A password

6. Continuous Assessment Login functionality (continued) Once a user has logged in, their name should be presented discretely on each page, e.g. if a username is ‘Frank’, there should be a simple message which says ‘Welcome, Frank’. Every page must contain a logout button which logs out a user and returns them to the homepage

7. Continuous Assessment User review functionality Users must be capable of entering one or more reviews for each album Each album on the website must display all user reviews, along with the username of the person who provided it The company have requested that a second MS Access database table be included to store these reviews  Each movie review record must contain: The movie to which the review refers The username of the reviewer The text of the actual review itself

8. CA – a 'how to' The steps required Create an MS Access database with a users table and a reviews table Each page must contain some php code that checks if a session variable called logged_in exists for that user  If yes, it should simply output Hello + that person's username, e.g. 'Hello Ruddiger' and a logout button that redirects to logout.php  If not, it should output a HTML form with (1) a username textfield (2) a password textfield (3) a 'login' button that sends this information to login.php

9. CA – a 'how to' The login.php page must  Connect to the users table in the MS Access database  Send a SQL query to this table requesting the password for that user  Compare the password provided with the password for that user in the database and if they match, create the logged_in session variable to store the user's name  Return to the homepage The logout.php page must  Destroy the logged_in session variable

10. CA – a 'how to' Each album page must  Contain PHP code that checks if a user is logged in and, if so, displays a form that includes (1) a textarea in which to type reviews and (2) a button to submit the review  Send this data to add_review.php when the button is clicked This add_review.php page must  Connect to the reviews table in the MS Access database  Send a SQL query to this table updating it with the new review, including the movie being reviewed, the review text, and the name of the user  Return to the homepage

11. A little bit on databases, while we’re here Database design is a huge area, about which we could (and people often do) speak for an entire module This class is intended to give you a working understanding of some concepts such that you can design a logical working database for a medium-sized Website

12. What is a database? A database is a central data store where data is recorded and maintained in some standardised way The data is organised in a way that allows both individual data items to be accessed, as well as related groups of data For our purposes, a database can often be thought of as a table, consisting of rows and columns  Each column represents one 'field', i.e. a set of values that an instance of a data type may possess  Each row represents one 'record', which states the values for one instance of that data type

13. What is a database? Imagine the following database IDFirstnameSurname 1EndaKenny 2EamonGilmore 3MicheálMartin 4GerryAdams 5JoeHiggins These columns represent 'fields' These rows represent 'records' Combined, fields and records represent one 'table'

14. Relational Keys Primary keys Usually one field in a table will act as the primary key  This key acts as a unique identifier for any particular record  As a result of this, the values in this field must be unique e.g. In a table of registered users, we might use email addresses or their screen name Foreign key We sometimes also have a field that acts as a foreign key to some other database table  This foreign key will match to the primary key in the other table, hence allow us to link together records across tables

15. Why do we use databases in Web Development? There are a number of cases where we want to store related groups of data, e.g.  Registered users of a Website, including their names, email address, etc.  Products that we sell, including specifications, price, etc.  Reviews of products that have been left, including who submitted the review, the date of the review, etc.

16. Designing a database As with all design, the first thing we must consider is what we are trying to achieve  We can then consider what information we need to store There are two basic approaches to database design  Top-down  Bottom-up

17. Top-down vs. bottom-up database design Top-down design  Usually begins with the question: what are the 'things' about which I want to store data?  Each 'thing' will be the type of record stored in one table  Next we ask, what characteristics of these 'things' are important?  These will be our fields Bottom-up design  Usually begins with the question: what data units do I need in order to make my site work?  These data units will be our fields  Next we ask, how do these group together?  Each group will be the type of record stored in one table

18. Top-down vs. bottom-up database design Advantages of top-down design  Can be used to make sure multiple developers are on the same page from the off  Allows for very systematic and logical design which may be easier to maintain  Starts simple Advantages of bottom-up design  Gets results quickly  More suitable where development of the website is iterative and changes are expected  Functionalities can be added/removed more easily

19. Database Management Systems A Database Management System (DBMS) is a software package designed to store and manage databases. This is different from a database file for several reasons  DBMS makes tables visible and generates reports  DBMS helps less technical users to use data efficiently  DBMS protects data from inconsistency and duplication due to multiple concurrent users  DBMS handles crash recovery  DBMS handles security and access control

20. Database Management Systems DBMS operates at the physical level This is where data handling becomes increasingly technical Physical model Logical model Conceptual model Management and business users Database administrators System analysts and designers

21. Database Management Systems (DBMS) A DBMS is a software program that allows us to create, use and maintain a database  These come in several categories  Desktop DB e.g. MS Access  Enterprise DB e.g. Oracle  Open Source DB e.g. MySQL We'll be using MS Access in this course

22. Want to read more? Links and references  An article on top-down vs. bottom-up information system design http://superprofundo.com/2010/12/13/top-down-and-bottom- up-pros-and-cons/ http://superprofundo.com/2010/12/13/top-down-and-bottom- up-pros-and-cons/  Nice article/book chapter on entity-relationship modelling http://www.databasedesign.co.uk/bookdatabasesafirstcourse/ chap3/chap3.htm http://www.databasedesign.co.uk/bookdatabasesafirstcourse/ chap3/chap3.htm