validated.php <?php $title="my basic page\n"; include("top.html"); print " hello, world "; include("bottom.html"); ?>

LIS651 lecture 2 Thomas Krichel

today introduction to mySQL more on PHP –functions –includes

Databases Databases are collection of data with some organization to them. The classic example is the relational database. But not all database need to be relational databases.

Relational databases A relational database is a set of tables. There may be relations between the tables. Each table has a number of record. Each record has a number of fields. When the database is being set up, we fix –the size of each field –relationships between tables

Example: Movie database ID| title | director| date M1| Gone with the wind | F. Ford Coppola| 1963 M2| Room with a view| Coppola, F Ford| 1985 M3| High Noon| Woody Allan| 1974 M4 | Star Wars| Steve Spielberg| 1993 M5| Alien| Allen, Woody | 1987 M6| Blowing in the Wind| Spielberg, Steven| 1962 Single table No relations between tables, of course

Problem with this database All data wrong, but this is just for illustration. Name covered inconsistently. There is no way to find films by Woody Allan without having to go through all spelling variations. Mistakes are difficult to correct. We have to wade through all records, a masochist’s pleasure.

Better movie database ID| title | director| year M1| Gone with the wind | D1| 1963 M2| Room with a view| D1| 1985 M3| High Noon| D2| 1974 M4 | Star Wars| D3| 1993 M5| Alien| D2 | 1987 M6| Blowing in the Wind| D3| 1962 ID| director name| birth year D1| Ford Coppola, Francis| 1942 D2| Allan, Woody| 1957 D3| Spielberg, Steven| 1942

Relational database We have a one to many relationship between directors and film –Each film has one director –Each director has produced many films Here it becomes possible for the computer –To know which films have been directed by Woody Allen –To find which films have been directed by a director born in 1942

Many-to-many relationships Each film has one director, but many actors star in it. Relationship between actors and films is a many to many relationship. Here are a few actors ID| sex| actor name| birth year A1| f| Brigitte Bardot | 1972 A2| m| George Clooney| 1927 A3| f| Marilyn Monroe| 1934

Actor/Movie table actor id| movie id A1| M4 A2| M3 A3| M2 A1| M5 A1| M3 A2| M6 A3| M4 … as many lines as required

databases in libraries Relational databases dominate the world of structured data But not so popular in libraries –Slow on very large databases (such as catalogs) –Library data has nasty ad-hoc relationships, e.g. Translation of the first edition of a book CD supplement that comes with the print version Difficult to deal with in a system where all relations and field have to be set up at the start, can not be changed easily later.

databases in web sites Lots of active web sites are driven by relational databases. All large active web sites are. The design of a active web site first involves looking at databases. In a shop situation, we have the following tables –customers –products –orders –orders_products for multiple to multiple relationship between orders and products.

SQL Once we have the relational database, we can ask sophisticated questions: –Which director has had the most female actors working for him? –In which years films have been shot that starred actors born between 1926 and 1935? Such questions can be encoded in a language know as “structured query language” or SQL. All relational database vendors implement a dialect of SQL.

mySQL They are a very successful, open-source vendor of SQL software. Their product is basically freely available. We will learn the mySQL dialect of SQL.

using mySQL mySQL is installed on wotan. Normally this involves logging into wotan and issuing commands to a character interface. The command would be –mysql -u user -p

create database This is a mySQL command to create a new database. Example –create database newbase; creates a database newbase

GRANT This is a command to create users and give them privileges. A simplified general syntax is GRANT privileges [columns] ON item TO user_name [IDENTIFIED BY 'password''] [WITH GRANT OPTION] If you use WITH GRANT OPTION, you allow the user to grant other users the privileges that you have given to her.

user privilegesI SELECTallows users to select (read) records from tables. INSERTallows users to insert new rows into tables. UPDATEallows users to change values in existing table rows. DELETEallows users to delete table rows. INDEX allows user to index tables

user privilegesII ALTERallows users to change the structure of the database. –adding columns –renaming columns or tables –changing the data types of tables DROP allows users databases or tables.

user privilegesIII CREATEallows users to create new databases or tables. If a specific table or database is mentioned in the GRANT statement, users can only create that database or table, which will mean that they have to drop it first. USAGEallows users nothing. This is a useful point to start with if you just want to create a user.

REVOKE This is the opposite of GRANT.

current setup As the super user, I did create database user_name; GRANT * ON user_name TO user_name IDENTIFIED BY 'secret_word'' WITH GRANT OPTION; Here –user_name is your wotan user name –secret_word is your secret word –* means all rights

create a web user You do not want to give the same access rights to people coming in from the web as you have. You do not want to do this. You personally have too many privileges. I have yet to find out how you can create a web user by yourself.

creating tables before you do it, set up some examples on a sheet of paper. Here is an example CREATE TABLE customers (custumer_id INT UNSIGNED NOT NULL AUTO_INCREMENT PRIMARY KEY, name CHAR(50) NOT NULL, ADDRESS CHAR(100) not NULL, CHAR(40), STATE char(2) not NULL);

column data types TINYINT can hold a number between -128 and 127 or between 0 to 255. BIT or BOOL are synonyms for the TINYINT. SMALLINT can hold a number between and or 0 and INT can hold a number between -2**31 and 2**31-1 or between 0 and 2**32-1. INTEGER is a synonym for INT. BIGINT can hold a number between -2**63 and 2**61-1 or between 0 and 2**64-1.

column data types: float FLOAT is a floating number on 4 bytes DOUBLE is a floating number on 8 bytes

column data types: dates DATE is a day from to TIME is a time from -838:59:59 to 838:59:59 DATETIME is a data and time, usually displayed as YYYY-MM-DD HH:MM:SS TIMESTAMP is the number of seconds since at 0 hours. This number may run out in 2037.

field options PRIMARY KEY says that this column is a the primary key. There can be only one such column. Values in the column must be unique. AUTO_INCREMENT can be used on columns that contain integer values.

functions The PHP function reference is available on its web site It shows the impressive array of functions within PHP. But one of the strengths of PHP is that you can create your own functions as you please. If you recreate one of the built-in functions, your own function will have no effect.

example Stephanie Rubino was an English teacher and objects to sentences like You have ordered 1 bottles of Grosswald Pils. Let us define a function rubino_print(). It will take three arguments –a number to check for plural or singular –a word for the singular –a word for the plural

function and parameters use the keyword "function" and declare your parameters, as in: function rubino_print ($number, $singular,$plural) { if($number == 1) { print "one $singular"; } else { print "$number $plural"; }

default arguments Sometimes you want to allow a function to be called without giving all its arguments. You can do this by declaring a default value. For the previous example function thomas_need($thing='beer') { print "I need $thing\n"; } thomas_need(); // prints: I need beer; thomas_need('sleep'); // prints: I need sleep;

rubino_print using common plurals function rubino_print ($num, $sing,$plur=1) { if($num == 1) { print "one $sing"; } elseif($plur ==1) { print "$num $sing"."s"; } else { print "$num $plur"; }

return value Up until now we have just looked at the effect of a function. return is a special command that return a value. When return is used, the function is left.

rubino_print with return function rubino_print ($number, $singular,$plural) { if($number == 1) { return "one $singular"; } return "$number $plural"; } $order=rubino_print(2,"beer","beers"); print "you ordered $order\n"; // prints: you ordered 2 beers.

visibility of variables variables used inside a function are not visible from the outside. Example $beer="Karlsberg"; function yankeefy ($name='Sam Adams') { $beer=$name; } yankeefy(); print $beer;// prints: Karlsberg the variable inside the function is something different than the variables outside.

accessing global variables. There are two ways to change a global variable, i.e. one that is defined in the main script. One is just to call it as $GLOBAL['name'] where name is the name of the global variable. function yankeefy ($name="Sam Adams") { $GLOBAL['beer']="name"; }

brewer_quiz.php: introduction <?php $brewers=array('Großwald Brauerei','Homburger Brauhaus', 'Karlsberg Brauerei','Ponter Hausbrauerei', 'Saarfürst Merziger Brauhaus','Mettlacher Abtei-Bräu','Körpricher Landbräu','Brauerei G.A. Bruch','Neufang Brauerei','Zum Stiefel'); $form_top=" \n"; $form_submit=' '."\n"; $form_end=' ';

brewer_quiz.php: form building function build_form($answer,$comment) { print " Take the Saarland brewery challenge \n"; print $GLOBALS['form_top']; print " "; print $GLOBALS['form_submit']; print $GLOBALS['submit_check']; print $GLOBALS['form_end']; print $comment; }

brewer_quiz.php: form processing function process_form($answer,$brewers) { $r[]=$answer; foreach($brewers as $brew) { if($answer == "$brew") { $r[]=' Congradulation! This is correct! '; return $r; } $r[]=' This is a bad answer, try again! '; return $r; }

brewer_quiz.php main part if($_GET['submitted']) { $from_form=process_form($_GET['guess'],$brewer s); } build_form($from_form[0],$from_form[1]) ; ?>

working with many source files Many times it is useful to split a PHP script into several files. PHP has two mechanisms. require(file) requires the to be included. If the file is not there, PHP exits with an error. include(file) includes the file.

require() and include() Both assume that you leave PHP. Thus within your included file you can write simple HTML. If you want to include PHP in your included file, you have to surround it by, just like in a PHP script. Here is an example to use include to build the basic web page.

bottom.html <i mg style="border: 0pt" src=" alt="Valid XHTML 1.0!" height="31" width="88" />

validated.php <?php $title="my basic page\n"; include("top.html"); print " hello, world "; include("bottom.html"); ?>

trouble $title in the top.html is not understood as the title. It reads as $title, which means "idiot" for your web user. Even if you replace $title with $title is empty. The definition from the outer file is not seen in the included file. So you have to split into three files, and print the title in the main file. I leave that to you to figure out.

Thank you for your attention!