This introduction is incidentally also an Introduction to the concept of a Content Mangement System also known as CMS, and therefor arguably most useful for your future careers.

A development project for a web based site, system or whatever you may call it, always starts with some kind of request, requirements from a client. This is by pure mindwork, no computer necessary. This semantic work produces a model of the information involved. We use a tool called Entity-Relationship modelling for this. It may look as follows:

The ER Model is purely semantic. We need to transform it into something logical, that may be understood by a computer. For this we use the Relational Model. Is has a language in which we express operations. This language is SQL, Structured Query Language, it translates the ER Modelling entities and relationships into tables with the attributes found in the ER model. It looks as follows:

drop database cms0;
create database cms0;
use cms0;

create table root (
    id int not null primary key auto_increment,
    name varchar(32) not null,
    slogan varchar(64) not null
) engine=innodb;

create table image (
    id int not null primary key auto_increment,
    filename varchar(32) not null,
    caption varchar(64) not null
) engine=innodb;

create table usesaslogo (
    rid int not null,
    iid int not null,
    primary key(rid),
    unique(iid),
    foreign key(rid) references root(id),
    foreign key(iid) references image(id)
) engine=innodb;

create table page (
    id int not null auto_increment,
    linktext varchar(16) not null,
    headline varchar(32) not null,
    content blob not null,
    rid int not null,
    primary key(id),
    foreign key(rid) references root(id)
) engine=innodb;

create table uses (
    pid int not null,
    iid int not null,
    primary key(pid,iid),
    foreign key(pid) references page(id),
    foreign key(iid) references image(id)
) engine=innodb;

create table navi (
    fraid int not null,
    tilid int not null,
    sort int not null,
    type char(1) not null,
    primary key(fraid,tilid),
    foreign key(fraid) references page(id),
    foreign key(tilid) references page(id)
) engine=innodb;

The final step into the computer, the transformation into a physical database is done by letting an SQL interpretor, a part of an RDBMD, read and interpet the SQL. Having the physical manifestation of the database we have an empty structure. We still need one useful ingredient in order to call it a database. We need data. Data is brought into the database by another part of SQL used for data manipulation. An example corresponding with the diagram, and the data structure:

insert into root (name, slogan) values('Muller''s Magic Manipulation', 'We Work Wonders');
insert into image (filename, caption) values ('mmmlogo.gif', 'Logo');
insert into image (filename, caption) values ('mmmlogo1.png', 'Logo');
insert into usesaslogo values(1,1);

insert into page (rid,linktext,headline,content) values(1, 'Home', 'The Story of the Logo', 'Cras facilisis justo ac nisi dignissim dapibus. Curabitur nec erat sem. Donec lectus magna, ullamcorper vel ullamcorper vitae, scelerisque vel nulla. Nam vel lorem sem. Donec cursus euismod nisi, sit amet scelerisque nulla varius eu. Integer massa leo, fermentum sed blandit euismod, rhoncus at elit. Nunc eu odio elit. Nam fringilla ullamcorper mauris, eget varius magna imperdiet nec. In hac habitasse platea dictumst. Aliquam erat volutpat. Aliquam id diam tellus, sed auctor turpis. Mauris mi eros, cursus vel aliquam ornare, suscipit vitae libero. Phasellus fermentum ultrices dapibus. Suspendisse est ipsum, varius eget scelerisque at, auctor eget elit.');
insert into page (rid,linktext,headline,content) values(1, 'Sales', 'MMM Sales', 'We horse around piching snake oil hither and dither');
insert into page (rid,linktext,headline,content) values(1, 'Accounting', 'MMM Admin', 'The department for creative book keeping, It has a stated target of avoiding taxes and other PITA formalia, aka red tape. Internally WE ARE the red tape.');
insert into page (rid,linktext,headline,content) values(1, 'Secret', 'MMM ?', 'If anyone knows what we do it''s Dogbert, ask him');
insert into page (rid,linktext,headline,content) values(1, 'Secret1', 'The Answer','42');

insert into navi values(1, 2, 10, 'A');
insert into navi values(1, 3, 90, 'A');
insert into navi values(1, 4, 20, 'A');
insert into navi values(2, 5, 40, 'B');

It is magic! This magic, and the logics behind it, you will learn in this semester.

Practically we shall work with PHP and the database programming language SQL. The paedagogical abstraction I have mentioned means that you will use SQL before you really know it in any detail. First we will use the PHP/SQL combination on a sample database we will fetch quite legally from the MySQL website.

We will check the validity of the download and installation by means of SQL. Upon that done succesfully we will do some recap of pure PHP, and finally move on to the combination of the two.