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Berner Fachhochschule-Technik und Informatik

Web Programming

5) PHP and MySQL

Dr. E. Benoist

Fall Semester 2010/2011

Web Programming 5) PHP and MySQL

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PHP and MySQL

Introduction

Basics of MySQLCreate a TableSee the content of a DBTables: Change rows and Insert data

Select Information

PhpMyAdmin

PHP and MySQL together

PDOmysql

Conclusion


2

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PHP and the Data BasesMySQL syntax

Create a new Data Base Set the rights for a DB Create tables Fill information into tables Select information (can sometime be very tricky)

Update informationPHP MyAdmin

A PHP program for managing MySQL BDs Graphical and practical

Do not require to log on the machine (only web access)PHP Library for MySQL

The old function-oriented library The new object-oriented library


Introduction 3

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MySQL a Data Base for theWeb

Open-Source DB

Free

Present in any Linux distribution

Available for fast any OS (Windows, Free-BSD, Mac-OS X,...)The perfect solution for web

LAMP architecture (Linux, Apache, MySQL, PHP) is one ofthe web standards

An application (phpMyAdmin) for managing the DB withoutshell access

Perfect integration within PHP.


Introduction 4

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Basics of MySQL commands

Creation functions (often done within PHP-MyAdmin)

Create a new table

Set the properties of fields (auto-increment, default value,...)

Routine functions (will be used in your programs)

Insert an element in a table

Select elements out of a table

Select elements out of many tables

Change the content of a record Delete some records


Basics of MySQL 5

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Creation of a tableSyntax

CREATE TABLE table name (definition of the fields)

Create a small table

CREATE TABLE category (

name VARCHAR( 100 ) NOT NULL ,categoryID TINYINT NOT NULL AUTO_INCREMENT ,

PRIMARY KEY ( categoryID )

);

Create a table with two fields

a string which length can not exceed 100

A primary key that is a counter


Basics of MySQL: Create a Table 6

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Create a new tableThe table can have fields of the following types:

TINYINT SMALLINT MEDIUMINT INT BIGINT that are integers(more or less long)

VARCHAR for short strings (smaller than 256 chars)

TEXT for texts with a fixed length (max 64 kB)

DATE date in format YYYY-MM-DD TIMESTAMP contains a unix timestamp

TIME format hh:mm:ss

DECIMAL number with a point.

FLOAT DOUBLE real numbers

BLOB Any Binary data (image, sound, long text, . . . )

. . .



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Create a new table (Cont.)

Other attributes or features

NULL or NOT NULL

AUTO INCREMENT for counters

The table has also properties

PRIMARY KEY

COMMENT description of the table



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Create other tablesThe article and vat tables

CREATE TABLE article (articleID INT NOT NULL AUTO_INCREMENT ,

name VARCHAR( 100 ) NOT NULL ,

vatID TINYINT NOT NULL ,

categoryID INT NOT NULL ,

Price DECIMAL NOT NULL ,PRIMARY KEY ( articleID )

);

CREATE TABLE vat (

vatID TINYINT NOT NULL AUTO_INCREMENT ,

rate DECIMAL NOT NULL ,

PRIMARY KEY ( vatID )

) COMMENT = The table containing VAT rates;



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See the content of a data base(Cont.)

See all columns of a table

mysql> show columns from vat;

+-------+---------------+------+-----+---------+----------------| Field | Type | Null | Key | Default | Extra

+-------+---------------+------+-----+---------+----------------

| vatID | tinyint(4) | | PRI | NULL | auto_increment

| rate | decimal(10,2) | | | 0.00 |

+-------+---------------+------+-----+---------+----------------



Basics of MySQL: See the content of a DB 11

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Change a Table - ALTER

Remove columns

ALTER TABLE t2 DROP COLUMN c, DROP COLUMN d;

Add a new column

ALTER TABLE article ADD description BLOB

NOT NULL ;

Change an existing column

ALTER TABLE article CHANGE Price price

DECIMAL( 10, 2 ) DEFAULT 0 NOT NULL;


Basics of MySQL: Tables: Change rows and Insert data 12

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Fill data into a table - INSERTSyntax

INSERT INTO tablename [(list of fields)] VALUES (list ofvalues);

all not null fields must be set, other can be just twocommas.

Insert a row in a table

INSERT INTO article ( articleID , name , vatID ,

categoryID , price , description )

VALUES (, Pencil, 0, 0, 1.50, );

Other possibility

INSERT INTO article values

(,Mercedes Class E,0,0,100000,

The same Mercedes Lady Diana has used

);



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Change the content of one ormany rows

UPDATE a table

UPDATE article SET description =

A very nice black pencil with white stripes

WHERE articleID = 1 LIMIT 1 ;



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Select informationSyntax

SELECT Field list FROM list of tables [WHERE conditions]

[LIMIT limits] Field list can also be a joker (*) Conditions can be combined with boolean connectors (AND,

OR, NOT)

If we only want to see a part of a list, we can limit it.Select all the rows and columns of a table

mysql> select * from vat;

+-------+------+

| vatID | rate |

+-------+------+

| 1 | 7.00 |

| 2 | 7.65 |

+-------+------+


Basics of MySQL: Select Information 15

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Merge data from differenttables

Merge two tables Fields must know from which table they come (the same field

can be in the two tables).

We can rename a requested field with the AS keyword.

mysql> select article.name, vat.rate, article.price

-> from article, vat where article.vatID= vat.vatID;

+------------------+------+-----------+

| name | rate | price |

+------------------+------+-----------+| Pencil | 7.00 | 1.70 |

| Mercedes Class E | 7.00 | 100000.00 |

+------------------+------+-----------+


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Merge ...(Cont.)

Merge and compute

mysql> select article.name, vat.rate, article.price,

-> article.price*(1+vat.rate/100) as priceWithVAT

-> from article, vat where article.vatID= vat.vatID;

+------------------+------+-----------+--------------+| name | rate | price | priceWithVAT |

+------------------+------+-----------+--------------+

| Pencil | 7.00 | 1.70 | 1.8190 |

| Mercedes Class E | 7.00 | 100000.00 | 107000.0000 |

+------------------+------+-----------+--------------+2 rows in set (0.00 sec)


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Join

INNER JOIN If there is no match, the row is not shownselect article.name, vat.rate, article.price

from article inner join vaton article.vatID= vat.vatID;

LEFT JOIN If there is no match, the second table is replaced byan empty record.

select article.name from article left join vaton article.vatID= vat.vatID

where vat.rate is null;(gives the list of articles with undefined VAT)


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More on SELECTResult of a select can be put into a temporary table

create temporary table valueVAT

(select vat.rate, article.name

from vat,article

where vat.vatID=article.vatID

);

You can access to the content and then delete this table

select * from valueVAT;

drop table IF EXISTS valueVAT;


S l d i

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Select and more optionsOrder result (DESC or ASC)

select name, price from article order by price desc;

Group rows

mysql> select vatID, count(vatID)

> from article GROUP BY vatID;

+-------+--------------+

| vatID | count(vatID) |

+-------+--------------+

| 1 | 2 |+-------+--------------+

1 row in set (0.00 sec)

SELECT can have a lot of functions an combine all of them


D l fi ld

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Delete fields

Delete the content of a table respectively to a where clause

delete from article where articleID=3;


Ad i i M SQL i h

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Administrate MySQL with aWeb interface

phpMyAdmin

A PHP program for managing MySQL Data Bases

Free available at http://www.phpmyadmin.net

Included in most of the Linux distrib Internationalization

Management made easyGenerate and displays the SQL query corresponding.

Create a new Data Base Create a new Table

Add or remove a column in a table

Web Programming 5) PHP and MySQLPhpMyAdmin 24

h M Ad i
http://www.phpmyadmin.net/http://www.phpmyadmin.net/

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phpMyAdmin

Management of data

Select data made easy

Update using a visual interface (does not work for BLOBs)

A lot of selection boxes containing all the possible values

Import / Export of data

Can create SQL Dump

Can export in a lot of formats: SQL, CSV, LaTeX, CSV forexcel, XML

With a lot of properties (zipped, gzipped, with delete tables ornot, . . . )


C l i

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Conclusion -MySQL/phpMyAdmin

Not as much powerful as other DBs

MySQL does not implement all of SQL

It is enough to handle a small web site

Very useful and easy to install, configure and managePHP supports all other DBs

Oracle

ODBC (MS-SQL server, Access)

Postgess

DBase

. . .


PHP d M SQL

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PHP and MySQL

Four Libraries

mysql old library

mysqli new library

pear MDB2 multi-database library and abstraction layer(merge of PEAR DB and Metabase abstraction layer)

PDO Object Oriented generic library

Web Programming 5) PHP and MySQLPHP and MySQL together 27

PHP d M SQL (C t )

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PHP and MySQL (Cont.)

mysql

Used from the beginning of the language

Compatible with a lot of existing code

mysqli

New since php5 Contains objects and encapsulation

PDO

Compatible with almost any Data Base

Syntax is the same and is platform independent

Not as optimized as the two dedicated routines

Web Programming 5) PHP and MySQLPHP and MySQL together 28

PHP Data Objects PDO

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PHP Data Objects - PDO

PDO is a generic connector for any database

Code is (almost) platform independant Support is provided for all major Data Bases servers (MySQL,

Oracle, MS SQL Server, Sybase, Informiy, ODBC, PostgreSQL,SQLITE)

PDO is an oject oriented interface

Creates a connection object Creates Statements and Results that are objects

Web Programming 5) PHP and MySQLPHP and MySQL together: PDO 29

Create a connection

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Create a connection The first step is to create a connection to the DB server

Needs an URL for connecting:

protocol:host=;dbname= Arguments are username and password

Close the connection by setting the handler to null


Execute a SQL query

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Execute a SQL query Execute a SQL Query : $dbh->exec($sql);

Value returned = number of affected rows

Should be used if no result set is returned (INSERT / UPDATE)

try {$dbh = new PDO(mysql:host=$hostname;dbname=animals,

$username, $password);

/ INSERT data /$sql = INSERT INTO article (name, price) VALUES (Journal, 1.9);$count = $dbh>exec($sql);/ echo the number of affected rows/echo $count;/ close the database connection /

$dbh = null;}catch(PDOException $e){

echo $e>getMessage();}


Update records

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Update records

PDO::exec() is used each time no selection is needed

/ INSERT data /

$query=UPDATE animals SET animal name=bruce;$query .= WHERE animal name=troy;$count = $dbh>exec($query);/ echo the number of affected rows /echo $count;


Select queries

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Select queries

SELECT returns a result set Method is PDO::query()

Returned statement can be visited like an array(implements the SPL traversible iterator)

/ The SQL SELECT statement /$sql = SELECT FROM animals;foreach ($dbh>query($sql) as $row)

{print $row[animal type] . .

$row[animal name] .
;}


Fetch the result set

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Fetch the result set There are multiple ways to visit a result set

The SPL traversible iterator (i.e. a foreach on the resultset

itself) Fetch the result in arrays or objects Fetch :

$result = $stmt->fetch(PDO::FETCH ASSOC); : Createsan associative array $result containing one record.

If fetch is repeated, moves one record ahead Visit with a while (fetch returns false at the end of the

selection)

$sql = SELECT FROM article;/ fetch into an PDOStatement object /

$stmt = $dbh>query($sql);while ($result = $stmt>fetch(PDO::FETCH ASSOC)){

echo Name = .$result[name]., price=.$result[price].
\n;}


Different types of Fetch

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Different types of Fetch Into an associative array:

$result = $stmt>fetch(PDO::FETCH ASSOC);...echo $result[name];

Into a numeric array

$result = $stmt>fetch(PDO::FETCH NUM)..echo $result[1]

Into both associative and numeric array

$result = $stmt>fetch(PDO::FETCH BOTH)..echo $result[1]., .$result[name];


Fetch into Objects

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Fetch into Objects

Fetch can create a ad-hoc object, having the columnsnames as properties

$obj = $stmt>fetch(PDO::FETCH OBJ);

/ Visit the object directly /echo $obj>name.
\n;echo $obj>price;


Fetch Lazy

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Fetch Lazy

PDO::FETCH LAZY is odd as it combines PDO::FETCH BOTHand PDO::FETCH OBJ.

$obj = $stmt>fetch(PDO::FETCH LAZY);

/ Visit the object directly /echo $obj>name.
\n;echo $obj[1].
\n;echo $obj[price];


Fetch a record into an object of

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Fetch a record into an object ofa given class

PDO::FETCH CLASS instantiates a new instance of thespecified class.

The field names are mapped to properties (variables) withinthe class called.

This saves quite a bit of code and speed is enhanced as themappings are dealt with internally.

method fetchALL() creates an array containing all the

records.


Fetch a record into an object of

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Fetch a record into an object ofa given class (Cont.)

class article{public $articleID;public $name;public $vatID;public $categoryID;public $price;public $description;public function displayElementLine(){

echo $this>name.,.$this>price.
\n;}

}

...$stmt = $dbh>query($sql);$obj = $stmt>fetchALL(PDO::FETCH CLASS, article);foreach($obj as $article){

$article>displayElementLine();}


Fetching into an new Object

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Fetching into an new Object

We define the fetch mode of a statement

$sql = SELECT FROM article;

/ fetch into an PDOStatement object /$stmt = $dbh>query($sql);

/ set the fetch mode with PDO::setFetchMode() /$stmt>setFetchMode(PDO::FETCH INTO, new article);

/ loop over the PDOStatement directly /foreach($stmt as $article){

$article>displayElementLine();}


Error Handling

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Error Handling

Default: Errors are Dye statements

Program is interrupted Error is displayed on Screen

We should throw exceptions Change the error mode such that it sends exceptions, Then catch all axceptions It prevents an attacker to access to internal information.


Error Handling (Cont.)

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Error Handling (Cont.)

try {

$dbh = new PDO(mysql:host=$hostname;dbname=animals,$username, $password);

/ echo a message saying we have connected /echo Connected to database
;/ set the error reporting attribute /

$dbh>setAttribute(PDO::ATTR ERRMODE,PDO::ERRMODE EXCEPTION);

...$dbh = null;

}catch(PDOException $e){

echo $e>getMessage();}


Prepared Statement

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p St t t A precompiled SQL statement

Accepts 0 or more parameters Usefull for using a query multiple times Usefull for preventing SQL Injection

$sql = SELECT FROM article.WHERE articleID = :article id OR name = :name;

$stmt = $dbh>prepare($sql);$stmt>bindParam(:article id, $article id, PDO::PARAM INT);$stmt>bindParam(:name, $name, PDO::PARAM STR, 5);$stmt>execute();$result = $stmt>fetchAll();

foreach($result as $row){echo $row[articleID]., ;echo $row[name]., ;echo $row[price].
\n;

}


Using a prepared statement

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g p p$article id = 6; $name = 20 Minuten;$sql = SELECT FROM article WHERE articleID=:article id OR name=:name;

$stmt = $dbh>prepare($sql);$stmt>bindParam(:article id, $article id, PDO::PARAM INT);$stmt>bindParam(:name, $name, PDO::PARAM STR, 5);$stmt>execute();$result = $stmt>fetchAll();foreach($result as $row){ echo $row[name].
\n; }

$article id = 5;$name = 24 Heures;$stmt>execute();$result = $stmt>fetchAll();foreach($result as $row){ echo $row[name].
\n; }$article id = 1;$name = Nesquik;$stmt>execute();$result = $stmt>fetchAll();foreach($result as $row){ echo $row[name]., ; }


Transaction

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Transactions are used to group requests that mustremain together

For efficiency reason (do not lock the file too many times) For consistency of database (Group some queries that should

remain together)

Examples

Insertion of many records Credit and Debit operations (Bookkeeping) Delivering and stock management . . .

Syntax

At the begining of the transaction$dbh->beginTransaction(); At the end of the transaction $dbh->commit(); In order to cancel a transaction (before commit)


Transaction (Example)

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( p )try{...

$dbh>beginTransaction();$table = CREATE TABLE animals (

animal id MEDIUMINT(8) NOT NULL AUTO INCREMENT PRIMARY KEY,animal type VARCHAR(25) NOT NULL,animal name VARCHAR(25) NOT NULL

);

$dbh>exec($table);$dbh>exec(INSERT INTO animals (animal type, animal name) VALUES (em...$dbh>exec(INSERT INTO animals (animal type, animal name) VALUES (liza$dbh>commit();echo Data entered successfully
;

}catch(PDOException $e){

$dbh>rollback();echo $sql .
. $e>getMessage();

}


Get the index of the last

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inserted element When inserting an element, index may be

autoinctemented

Programmer needs a way to access the index Can update other tables Can create cross reference with new records

/ INSERT a new row /$sql = INSERT INTO article (name, price) VALUES (Laptop, 500);$dbh>exec($sql);

/ display the id of the last INSERT /echo The last inserted element has ID: ;echo $dbh>lastInsertId().
\n;


PHP and MySQL together: PDO 47

Use the Singleton pattern for

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g pthe connection object

Connection to the DB should be unique

Connection requires a lot of time Number of connections to the DB may be limited

A design Pattern exists for creating only one instance of

a class The singleton design pattern

Ideas:

Make the constructor private Make the clone private

Create an instance as class parameter Create a static method getInstance() that creates the

instance if it did not exist or returns the existing one.



The Singleon

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class db{private static $instance = NULL;private function construct() {

/ maybe set the db name here later /}public static function getInstance() {

if (!self::$instance){

self::$instance = new PDO(mysql:host=localhost;dbname=example, root, );;

self::$instance> setAttribute(PDO::ATTR ERRMODE,PDO::ERRMODE EXCEPTION);

}

return self::$instance;}private function clone(){ }

} / end of class /



Usage

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try {

/ query the database /$result = DB::getInstance()>query(SELECT FROM article);

/ loop over the results /foreach($result as $row)

{print $row[name] . . $row[price] .
;

}}catch(PDOException $e)

{echo $e>getMessage();

}



mysql :(The old library)

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PHP and MySQL together: mysql 51

Connection to a DB

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Establish the connection

$db = @mysql connect(localhost,root,toto14);Handle

Returned by the connection

One can play with more than one connection (multi-server)

Is a number

Error handling

echo mysql error();

Disconnect from the DB

mysql close();



Execute Queries

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execute a SQL query: mysql query(sql,conn)SQL queries are stored in an array and executed

require(connDB.php);

$querys= array();

$querys[]=insert into article values(0,Milk,1,1,.10.90,Super milk for the kids);;

$querys[]=insert into article values(0,Cafe,1,.1,10.90,Super cafe for the adults);;

foreach($querys as $query){mysql query($query , $conn);

}mysql close($conn);



Fetch result of a select

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require once(connDB.php);

$query = select from article;

$result = mysql query($query , $conn);

if($result){$nbRows = mysql num rows($result);echo $nbRows have been selected by query:
$query
\n;

// arrayType can be : MYSQL ASSOC, MYSQL NUM, MYSQL BOTHwhile( $row = mysql fetch array($result, MYSQL ASSOC)){

echo implode(,,$row).
\n;}

}else{echo mysql error();




Fetch result of a select (Cont.)

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Types of arrays

MYSQL ASSOC keys are field names

MYSQL NUM keys are numbers

MYSQL BOTH keys are both numbers and field namesfetch a single row until no more is accessible

while( $row = mysql fetch array($result, MYSQL ASSOC))



Fetch a row into an object

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Creates an object whose member variables are fields

if($result){$nbRows = mysql num rows($result);echo $nbRows have been selected by query:
$query
\n;while( $obj = mysql fetch object($result)){

echo {$obj>name}, => CHF {$obj>price}
\n;}

}



Insert data into a table

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$query = insert into article values(0,Milk UHT, .1,1,7.90,Super milk for kids);

$result= mysql query($query , $conn);

if(!$result){echo mysql error;

}$newID = mysql insert id();

$query2 = update article set price=5.5. where articleID=$newID;

$result2= mysql query($query2 , $conn);

if(!$result2){die(Could not execute $query2 .mysql error());}$affectedRows = mysql affected rows($conn);echo number of affected rows:$affectedRows
\n;



Insert and Update

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Insert

Create a new record in the table

ID automatically generated (with auto increment)

We need to access this counter:

$newID = mysql insert id();

Update

Useful to change the tables

Programmer want to know if it worked

Indication: the number of affected rows: mysql affected rows($conn)



Manipulate the Data Base itself

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require once(connDB.php);$res = mysql list dbs($conn);

for($i=0;$i < mysql num rows($res);$i++){$dataBase= mysql tablename($res,$i);$result=0;$query = show tables from $dataBase;$result = mysql query($query , $conn);if($result){

$nbTables = mysql num rows($result);echo $dataBasehas $nbTables tables
\n;

while( $row = mysql fetch array($result,MYSQL ASSOC)){

echo implode(,,$row).
\n;

}}




Conclusion I

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mysql Library Uses no objects,

Based and handles that can be passed as parameters tofunctions

PDO Generic Access to any database

Most of the code is plattform independant

Must sometime be adapted


Conclusion 60

Conclusion II

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DB are the center of our work

Do not require a programmer to write HTML

they are used to access DBs

forms and dbs are the two pillars of web programming

a lot of other finesses to be discovered SQL : a semester course of 2 hours a week

PHP supports all data bases

A standard web architecture is LAMP: Linux Apache MySQL

PHP


Conclusion 61

Resources

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Pear Documentationhttp://pear.php.net


Conclusion 62
http://pear.php.net/http://pear.php.net/

Documents

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