PHP Programming

Transcript PHP Programming

PHP Programming
Topics
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Background and History of PHP
Installation
Comments in PHP
Variables
Conditions
Loops
Functions
File Handling
Database Handling (MySQL, MSSQL, ODBC)
Background
• Personal Home Page – C kind of scripts
written in Perl language, by Rasmus
Lerdorf in 1995.
• He called the language as PHP/FI –
Personal Home Page / Forms Interpreter.
• 1997 Version 2.0 was released
• Then came 3.0, 4.0. They were called
PHP simply
• Recent version is PHP 5.2.3
Installation
• Apache server need to be installed first
• The config file for apache server will be present
in the conf folder under the apache installed
directory
• Set the DocumentRoot to the path where the
PHP files will be stored
• Install PHP. Point apache conf directory when it
asks so and select the appropriate web server.
• Move the PHP.ini file to C:\WNDOWS directory
PHP Comments
• All php files are saved with extension .php
• The can be written in notepad or any text
editor
• Single line comment
– // this is single line comment
• Multi line comment
– /*….
This is a multi line comment */
Sample PHP
<html>
<body>
<?php echo “hello”; ?>
</html>
The above program will display hello in the
browser
Variables
• Variables start with a $ symbol
• Variables can contain _ or numbers or
alphabets
• $ should be followed by _ or alphabet and
not by a number
• PHP is loosely typed language. There is
no strict data typing
• Variable can be assigned with any values
Conditions
• If else
if(condn) {….}
elseif(condn) {….}
else { ….}
• Switch case
switch(var)
{
case c1: statements;break
.
.
Default: statements; break;
}
Loops
• For
for(intialisation;condition;increment/decrement)
{ statements }
• While
while(condn) { ….}
• Do While
do {….} while(condn);
Functions and Parameters
• PHP functions need to be defined with key
word function
• It can have zero or more values
(parameters)
• Functions may or may not return values
• If a function need to return value, the last
statement of the function should be return
– return value;
Functions
• Parameter less function
<?php
function sayHi()
{
echo “hi”;
}
?>
This can be called as <?php sayHi(); ?> in the
program
Functions
• Parameterized function
<?php
function greet($name)
{
echo “Hello “ . $name;
}
?>
This can be called <?php greet(‘Ram’);?>
This gives an output Hello Ram
Functions
• Function returning value
<?php
function add($a,$b)
{
return ($a + $b);
}
?>
When called like <?php echo add(1,2);?> we will
get an output 3 in the browser.
File Handling
• This involves 5 tasks
– Opening a file
– Reading data from a file
– Displaying the read data
– Writing contents to another file
– Closing a file
Opening a file
• $fp = fopen(‘filename’,’mode’);
• Eg $fp = fopen(‘c:\abc.txt’,’r’);
– This opens a file abc.txt in read only mode
• Available modes:
– r – read only
– w – write only
– w+ - read write
– A – append – adding to the end
Reading a file
• Several methods are available
– fread(filepointer,no of bytes to read)
– fgetc(filepointer) – Reads character by character
– fgets(filepointer) – Reads line by line
• The read content can be stored in a variable
• $data = fread($fp,10) – this reads 10 characters
from file pointed by file pointer $fp and stores in
$data
• If we want to read characters till end, we need to
use a loop with condition checking for End of
File
Writing to file
• We can use echo $data, to print the contents
read from the file to browser
• Or we can open another file in write mode and
put the contents to that file using either of these
methods
– fwrite(filepoiner,data);
– fputc(filepointer,char); - writes character by character
– fputs(filepointer,line); - writes line by line
• Eg - fwrite($fpw,$data);
Closing a file
• feof(fp) – Checks for end of file.
• Returns –1 if EOF is reached. Otherwise
returns 0
• To close a file use fclose(filepointer)
method
• Eg. fclose($fp);
– This closes the file pointed by $fp.
Database Handling
• PHP can connect to
– MySQL
– MSSQL
– Access and other databases like oracle,
postgre sql etc
• There are separate methods available for
connecting to the databases
MySQL and MSSQL Connection
• mysql_connect(dbserver,userid,password)
• mssql_connect(dbserver,userid,password)
– These methods are used for connecting to MySQL
and MSSQL server using a userid and password
• $con = mysql_connect(‘localhost’,’root’,’root’);
– This gets a connection to the local mysql server using
the credentials root and root
– If server cannot be connected, it will throw an error
stating the problem
• Note: Mysql and MSSQL can be accessed in identical
way except for the preceeding mysql or mssql. So will
use mysql henceforth.
MySQL Select DB
• mysql_select_db(connection,dbname)
• mysql_select_db($con,”test”);
–This will select the db test under the
server localhost
–If unable to select the database, an
error will be thrown
MySQL Execute Query
• mysql_query(connection,sql statement);
• This will execute the sql statement on the
database and store the result in a variable
• Eg
– $rs = mysql_query($con,select stmt);
– The rows of select statement will be stored in $rs
– $row = mysql_fetch_array($rs);
• This will fetch a row and store in $row
• Values can be accessed like - $row[“ID”] – returns value of
column ID in the fetched row.
MySQL and MSSQL Close
• To close a db connection we have close
method
– mysql_close(connection);
– mssql_close(connection);
• Example
– mysql_close($con);
– mssql_close($con);
ODBC Data handling
• Connect to a data source
– odbc_connect(dsn,uname,pwd);
– DSN – Data Source Name
– Go to Control Panel -> Administrative Tools ->
Datasources (ODBC)
– Click on ODBC and select System DSN tab.
– Click Add and choose Access Database
(mdb) and click Finish
– In the dialog that appears, give DSN Name
and Description
ODBC Data handling Contd..
– Click on Select under Database section
– Choose a mdb (access database file) and
give OK
• $conn=odbc_connect('nwind','','');
– Here nwind is the DSN that we have created
in our system to access a database
– We have not given any user name or
password during DSN creation
– So those fields are left empty.
Selecting rows from a table
• $rs = odbc_exec($conn,$sql);
– $conn – connection string
– $sql – SQL query to select rows from table
– $rs is the result set of the query execution
• odbc_fetch_row($rs)
– This command fetches row by row from the result set
• $cid = odbc_result($rs,"CustomerID");
– This command fetches value for the column
CustomerID from the current row and stores it in the
variable $cid.
Closing Connection
• odbc_close(connection)
– This function closes the connection obtained
and releases the same to the connection pool
• odbc_close($conn);
– The connection defined by $conn is released
and no query can be executed using this
connection variable hence forth.

PHP Programming

Transcript PHP Programming

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