PHP and MySQL with snapshots

Introduction
PHP is an acronym for "PHP Hypertext Preprocessor“.
PHP is a widely-used, open source scripting language.
PHP scripts are executed on the server.
PHP costs nothing, it is free to download and use.
PHP is simple for beginners.
PHP also offers many advanced features for professional
programmers.
What is a PHP File?
PHP files can contain text, HTML, CSS, JavaScript, and PHP code.
PHP code are executed on the server, and the result is returned to the
browser as plain HTML.
PHP files have extension ".php“.

Why PHP
PHP runs on various platforms (Windows, Linux, Unix, Mac OS X, etc.)
PHP supports a wide range of databases.
PHP is free. Download it from the official PHP resource: www.php.net.
PHP is easy to learn and runs efficiently on the server side.
How to run PHP files?
localhost/foldername/filename
Resource:
Xampp
 Combines an Apache web server, PHP, and MySQL into one
simple installation service.
 Very little configuration required by the user to get an initial system
up and running.
 http://www.apachefriends.org/en/xampp.html

Variables in PHP
Variables in PHP are denoted by a dollar ($) sign followed by the name
of the variable.
Variable names are case sensitive ($y and $Y are two different
variables).
A variable name cannot start with a number.
A valid variable name starts with a letter or underscore, followed by any
number of letters, numbers, or underscores.

 An array can store one or more values in a single variable name.
Each element in the array is assigned its own ID so that it can be easily
accessed.
$array[key] = value;
An array in PHP is a structure which maps keys to values .
The keys can specified explicitly or they can be omitted.
If keys are omited, integers starting with 0 are keys.
The value mapped to a key can, itself, be an array, so we can have
nested arrays.

Numeric Array
An Array with numeric index.
A numeric array stores each element with a numeric ID key.
Automatically array:
Example:
$names = array("Peter","Quagmire","Joe");

Manually array
<?php
$lang[0]="PHP";
$lang[1]="Perl";
$lang[2]="Java";
$lang[3]=".Net";
echo "<b>" .$lang[0]. "
and " .$lang[1]. " are
programming
languages.";
?>

Associative Array
An array where each ID key is associated with a value.
An array with strings index. This stores element values in association
with key values rather than in a strict linear index order.
When storing data about specific named values, a numerical array is
not always the best way to do it.
It is the combination of keys and values.
Associative array will have their index as string so that you can
establish a strong association between key and values.
Syntax:
$arr_name=array(“key”=>value, “key”=>value);

Example:
<?php
$lang ['php']="10";
$lang ['perl']="5";
$lang ['java']="2";
echo "php language is
".$lang ['perl']. "years
old.";
?>

Multidimensional Array
An array containing one or more array.
In a multidimensional array, each element in the main array can also be
an array.
And each element in the sub-array can be an array, and so on.
Syntax:
$ main_Array=array
(
“sub-array=>array(
“PHP”,
“perl”
)
);

Example:
<?php
$array=array(
"php"=>array(
"php1",
"php",
"php5"
),
"perl"=>array(
"perl5"
)
);
echo "<b>". "Is " . $array ["perl"]
[0] . " programming language?";
?>

Array-manupulation functions
PHP provides a huge set of array-manipulation
functions. Some of them are given below:
array -- Create an array
Mixed_array –integers and strings
current_array-Return the current elements in the array
array_key_exists -- Checks if the given key or index exists in the array
array_keys -- Return all the keys of an array
array_merge -- Merge two or more arrays
array_merge_recursive -- Merge two or more arrays recursively
array_walk -- Apply a user function to every member of an array
arsort -- Sort an array in reverse order and maintain index association
asort -- Sort an array and maintain index association
compact -- Create array containing variables and their values
count -- Count elements in a variable
current -- Return the current element in an array
.

Examples:
Array count
<?php
$a[0]=1;
$a[1]=2;
$a[2]=5;
$result= count($a);
echo $result;
?>

Combine array
Creates an array by
using one array for keys
and another for its value
Example:
<?php
$a=array("green","red",
"yelllow");
$b=array("avocoda","apple"
,"banana");
$c=array_combine($a,$b);
print_r($c);
?>

Array Sort
Sort an array (according
to alphabet)
Example:
<?php
$fruits=array("lemon","orange"
,"banana");
sort($fruits);
foreach ($fruits as $keys
=>$val)
{
Echo "fruits <br>[". $keys ."]=".
$val ."";
}
?>

Strings
String is a series of character. Save as bytes.
A string literal can be specified in three different ways:
 single quoted
 double quoted

Single-quoted Strings
In single-quoted strings, single-quotes and backslashes must be
escaped with a preceding backslash
Example usage
echo 'this is a simple string';
echo 'You can embed newlines in strings,
just like this.';
echo ‘Douglas MacArthur said "I'll be back” when leaving the Phillipines';
echo 'Are you sure you want to delete C:*.*?';

Double-quoted Strings
In double-quoted strings,
 variables are interpreted to their values, and
 various characters can be escaped
 n linefeed
 r carriage return
 t horizontal tab
 backslash
 $ dollar sign
 ” double quote
 [0-7]{1,3} a character in octal notation
 x[0-9A-Fa-f]{1,2} a character in hexadecimal notation

String-manipulation functions
PHP provides huge range of string-
manipulation functions:
 addcslashes -- Quote string with slashes in a C style
 addslashes -- Quote string with slashes
 count_chars -- Return information about characters used in a string
 echo -- Output one or more strings.
 explode -- Split a string by string
 implode -- Join array elements with a string
 join -- Join array elements with a string
 ltrim -- Strip whitespace from the beginning of a string
 md5 -- Calculate the md5 hash of a string
 strpos -- Find position of first occurrence of a string

 stristr -- Case-insensitive strstr()
 strrchr -- Find the last occurrence of a character in a string
 str_repeat -- Repeat a string
 strrev -- Reverse a string
 strrpos -- Find position of last occurrence of a char in a string
 strspn -- Find length of initial segment matching mask
 strstr -- Find first occurrence of a string
 strtolower -- Make a string lowercase
 strtoupper -- Make a string uppercase
 str_replace -- Replace all occurrences of the search string with the
replacement string
 strncmp -- Binary safe string comparison of the first n characters
Some examples are given next:

Examples:
strlen:
Get string length.it also include
space.It counts from 1.
<?php
$str="bebo technology";
$result=strlen ($str);
echo "the string length is $result";
echo "<br>";
?>
Syntax: strlen(string);

Examples
Strpos
This function return the position of
particular character in string. It
counts from 0.
Example:
<?php
$numbered_string="1234567890";
$five_pos=strpos($numbered_string,
"5");
echo "the position of 4 in our string is
" . $five_pos;
?>
Syntax:
Strpos(string,”char position to be
found”)

Examples:
explode function
The explode function break a
string Into array.
<?php
$array="welcome to btes";
print_r (explode (" ","$array"));
?>
Syntax:
explode (seprator,string);

Examples:
Implode function
join array elements with a string.
<?php
$array=array('kunika', 'verma',
'B.tech');
$comma_seprated=implode (", ",
$array);
echo $comma_seprated;
?>
Syntax:
implode (seprator,string);

Include() and require()
functions

INCLUDE AND REQUIRE
FUNCTIONS
PHP include and require Statements
In PHP, you can insert the content of one PHP file into another PHP file
before the server executes it.
The include and require statements are used to insert useful codes
written in other files, in the flow of execution.
Include and require are identical, except upon failure:
Require will produce a fatal error (E_COMPILE_ERROR) and stop the
script.
Include will only produce a warning (E_WARNING) and the script will
continue.
Including files saves a lot of work. This means that you can create a
standard header, footer, or menu file for all your web pages. Then,
when the header needs to be updated, you can only update the header
include file.

PHP include and require
statement
Syntax:-
include 'filename';
or
require 'filename';
Example:
Assume that you have a standard header file, called "header.php". To
include the header file in a page, use include/require:
<html>
<body>
<?php include 'header.php'; ?>
<h1>Welcome to my home page!</h1>
<p>Some text.</p>
</body>
</html>

Example 2:
Assume we have a standard menu file that should be used on all pages.
"menu.php":
echo '<a href=“#">Home</a>
<a href=“#">Tutorials</a>
<a href=“#">About Us</a>
<a href=“#">Contact Us</a>';
All pages in the Web site should include this menu file.
<html>
<body>
<div class="leftmenu">
<?php include 'menu.php'; ?>
</div>
<h1>Welcome to my home page.</h1>
<p>Some text.</p>
</body>
</html>

While loop
The while loop executes a block of code as long as the specified
condition is true.
Syntax:
while (condition is true)
{
code to be executed;
}
The example below first sets a variable $x to 1 ($x=1;). Then, the while
loop will continue to run as long as $x is less than, or equal to 5. $x will
increase by 1 each time the loop runs ($x++;):

Example:
<?php
$x=1;
while($x<=5)
{
echo "The number is: $x <br>";
$x++;
}
?>

Do-while loop
The do...while loop will always execute the block of code once, it will then
check the condition, and repeat the loop while the specified condition is
true.
Syntax
do
{
}
while (condition is true);
The example below first sets a variable $x to 1 ($x=1;). Then, the do
while loop will write some output, and then increment the variable $x
with 1. Then the condition is checked (is $x less than, or equal to 5?),
and the loop will continue to run as long as $x is less than, or equal to
5:

Example:
<?php
$x=1;
do
{
echo "The number is: $x
<br>";
$x++;
}
while ($x<=5)
?>

for: The for loop is used when you know in advance how many times the
script should run.
Syntax:
for (int counter; testcounter; increment counter)
{
}
Parameters:
intcounter: Initialize the loop counter value
test counter: Evaluated for each loop iteration. If it evaluates to TRUE,
the loop continues. If it evaluates to FALSE, the loop ends.
increment counter: Increases the loop counter value
For loop

foreach Loop
The foreach loop works only on arrays, and is used to loop through each
key/value pair in an array.
Syntax:
foreach ($array as $value)
{
}
For every loop iteration, the value of the current array element is
assigned to $value and the array pointer is moved by one, until it
reaches the last array element.

Example:
<?php
$a=array(1,2,3,4,5);
foreach ($a as $value)
{
?>
<div style="background-color:pink;
width:50;">
<?php echo $value; ?>
</div>
</br>
<?php } ?>

PHP is designed to work with the MySQL database. However, it can
also connect to other database systems such as Oracle, Sybase, etc.,
using ODBC.
Handles very large databases; very fast performance.
Why are we using MySQL?
 Free (much cheaper than Oracle!)
 Each student can install MySQL locally.
 Easy to use Shell for creating tables, querying tables, etc.
 Easy to use with Java JDBC

PHPMY ADMIN
phpMyAdmin
is a free and open source tool written in PHP intended to handle
the administration of Mysql with the use of a web browser. It can
perform various tasks such as creating, modifying or
deleting databases, tables, fields or rows;
executing SQL statements; or managing users and permissions.
Syntax:
localhost/phpmyadmin

How to connect with PHP?
Use the My SQL connect routine
 mysql_connect($host, $user, $password)
 $user and $password will be your account details
Mysql_connect will return a link ID
 $link = mysql_connect($host, $user, $password)
 if(!$link) { echo “Unable to connect”; }
Always check the link to ensure that the database connection was
successful

Selecting a database
Once a link has been established, select a database
 mysql_select_db($dbname, [$link])
 []optional – uses last created $link if not given
mysql_select_db returns a Boolean indicating status
$result = mysql_select_db(“students”)
If(!$result) { echo “No database”; }

How to create database in
Mysql

How to create tables
in Mysql
Click on your database
name.
Then create table
option will show.
It all show in fig:

Query types:
Insert query
Select query
Delete query
Update query
Join query

INSERT Query:
INSERT INTO
INSERT INTO [table]([fields,…]
VALUES([newvalues,…]).
[table] indicates which table to
insert into.
[fields] is a comma separated list
of fields that are being used.
[newvalues] is comma separated
list of values that directly
correspond to the [fields].
Syntax:
“insert into managenews(fields)
(values)”;

Selection query:
SELECT
 SELECT [fields,…] FROM
[table] WHERE [criteria]
ORDER BY [field] [asc,desc]
[fields] can be * for all or field
names separated by commas
[table] is the name of the table to
use.
Syntax:
“select * from
managenews(tablename)”:

Delete Query:
DELETE
 DELETE FROM [table]
WHERE [criteria]
Simple and dangerous statements
[table] to delete from
[criteria] specifying records to
delete
 No criteria deletes all records.
Syntax:
“delete from
managenews(tablename)”;

Update Query:
UPDATE
 UPDATE [table] SET
[field=value,…] WHERE
[criteria]
[table] denotes the table to update
[field=value,…] is a comma
separated list of values for fields
Syntax:
“update managenews(table name)
set
(field=‘value’)”;
Quick example:
$query = “UPDATE managenews
SET news='$news',date='$date‘
where id=".$id;
$result = mysql_query($query);
If(!$result)
{
echo “Update failed!”;
}
else
{
echo “Update successful!”;
}

Join Query:
JOINs can be used to combine tables.
A join can be classified in the from clause which list the two input
relations.
Types of joins:
1) Join
2) Inner join
3) Outer join
4) Left join
5) Right join

How to Join:
Consist full data which we
Show in our Query.
Syntax:
select Persons.Firstname,
Persons.Lastname,
Orders.Orderno from Persons
JOIN Orders ON
Persons.P_Id=Orders.P_Id
Output:

Inner join:
Simplest type of join
Also called: Equality join, Equijoin,
Natural join
VALUES in one table equal to
values in other table
Syntax:
Persons.Lastname,
INNER JOIN Orders ON
Syntax:

Outer join
Outer joins return
 all rows from one table (called
inner table) and
 only matching rows from
second table (outer table)
Fields are different in outer join
Syntax:
Persons.Lastname,
OUTER JOIN Orders ON

Left Join:
Left join pick the left outer cell
data.
Syntax:
Persons.Lastname,
LEFT JOIN Orders ON

Important:
Distinct: Count one for duplicate enteries.
Syntax:
Select distinct (category) from (tablename).
Limits: limit the counting for display.
Syntax:
select * from products (tablename) limit 0,10
Order by: set by ascending or descending order
Syntax:
Select * from (tablename) order by (productname) ASC
DESC
Ob_start(); if we use 2 headers on same page. use before html.
Ob_flush(); closing tag after html closing tag.

70
Accessing Query Result
Information
The mysql_num_rows() function returns the number of rows in a
query result
The mysql_num_fields() function returns the number of fields in a
query result
Both functions accept a database connection variable as an argument
The mysql_query() function sends SQL statements to MySQL
You use the mysql_create_db() function to create a new database
The mysql_select_db() function selects a database
You use the mysql_drop_db() function to delete a database
mysql_fetch_array() for fetch array by rows.

PHP and MySQL with snapshots

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