Php & my sql

Why PHP
 Open Source
 Very good support
 C/Java like language
 Cross Platform (Windows, Linux, Unix)
 Powerful, robust and scalable

PHP Elements
 Variables: placeholders for unknown or changing
values
 Arrays: a variable to hold multiple values
 Conditional Statements: decision making
 Loops: perform repetitive task
 Functions: perform preset task or sub task

PHP statements
<?php
your statement is here;
don„t forget to end each statement with semicolon
(“;”);
anything within this scope must be recognized by
php or you‟ll get error;
?>

Naming variables
 Start with dollar sign ($)
 First character after $ cannot be number
 No spaces or punctuation
 Variable names are case-sensitive
 You‟re free to choose your own but …
 … meaningful naming is much better.

Assigning values to variables
 $myVar = $value;
 $myVar = 3.4; # assign a number
 $myVar = “I‟m cute”; // Assign a string
 $myVar = $yourVar; /* assign a variable */
 $myVar = “$name is a terrible creature”;

PHP Output & comments
 echo:
 echo “you‟re a creature”; // print you‟re a creature
 echo $name; /* print value of variable $name */
 echo(“my creatures”); # print my creatures
 print:
 print “you‟re a creature”;
 print $name;
 print(“my creatures”);
 Also printf and sprintf

Joining together
 Joining string
 $var = “Digital”.”Multimeter”;
 Joining variables
 $var = $var1.$var2.$var3……. ;
 $var = “$var1 $var2 $var3 …… “;
 Joining string and variable
 $var = $var1.”Zener diode”;
 $var .= “blogger”;

Calculation

Operation Operator Example
Addition + $x + $y
Subtraction - $x - $y
Multiplication * $x * $y
Division / $x / $y
Modulo Division % $x % $y
Increment ++ ++$x @ $x++
Decrement -- --$x @ $x--

Array
 Declaration
 $RGBcolor = array(“red”, “Blue”, “Green);
 $mycar[] = “Rapide”;
 Access
 $myarray[element number]
 Functions
 array_pop(); array_push(); array_rand();
array_reverse; count(array); sort(array);
print_r(array)

Making decision (if, if else, elseif)
if(condition is true) {
//code will be executed here
}
if(condition is true) {
//code will be executed here
}
else {
//code will be executed if condition is false
}
if(condition 1) { }
elseif (condition 2) { }
else { }

Comparison operator
Symbol Name
== Equality
!= Inequality
<> Inequality
=== Identical
!== Not identical
> Greater than
>= Greater/equal than
< Less than
<= Less or equal than

Logical Operators
Symbol Name Use
&& Logical AND True if both operands are true
and Logical AND Same as &&
|| Logical OR True if not both operands are
false
or Logical OR Same as ||
xor Exclusive OR True if one of operands is true
! NOT Test for false

Switch statement
switch(variable being tested) {
case value1:
statement;
break;
case value2:
statement;
break;
.
.
.
.
default:
statment
}

Conditional (ternary) operator
 condition ? value if true : value if false;
$age = 17;
$fareType = $age > 16 ? 'adult' : 'child';

Loop
 while(condition is true) { statement; }
 do { statement; } while (condition is true);
 for(initial value; test; increase/decrease)
{statement;}
 foreach(array_name as temporary variable) {
statement;}

Breaking loop
 break: exit loop;
 continue: exit current loop but continue next
counter

PHP Function
 A block of code that performs specific task
represented by a name and can be called
repeatedly.
function function_name()
{
//code is here
return var; // may return value
}

Date & Time
 time(): timestamp from 1st January 1970
 date(format, timestamp):
 Format:-
 d: day of the month (1-31)
 m: month (1-12)
 Y: year in 4 digits
 Timestamp (optional)
 Default is current date and time
 Date Add / Date Diff
 Under DateTime class: DateTime:add, DateTime:diff

String function
 strlen(str): string length
 strpos(str, str_find, start): find string occurance
 strrev(str): string reverse
 substr(str, start_str, length): return part of string
 substr_replace(str, replacement, start, length):
replace part of string

Math Function
 Absolute value: abs(0 – 300)
 Exponential: pow(2, 8)
 Square root: sqrt(100)
 Modulo: fmod(20, 7)
 Random: rand()
 Random mix & max: rand(1, 10)
 Trigonometry: sin(), cos(), tan()

Building Form & input
 <form action=“” method=“URL” enctype=“data">
</form>
 method: get or post
 action: URL to be accessed when form is submitted
 enctype: type of data to be submit to the server
 All inputs must be within the form
 Textfield = <input type=“text” name=“”>
 Checkbox = <input type=“checkbox” name=“”>
 Radio Button = <input type=“radio” name=“”>
 Textarea = <textarea name=“”></textarea>
 List = <select name=“”><option
value=“”></option></select>

Getting information from form
 print_r($_POST): form data retrieval in array
 $_POST: contains value sent through post
method
 $_GET: contains value sent through get method

MySQL function (connection)
 Connection to database
 mysql_connect(servername, username,
password)
<?php
$test = mysql_connect(“localhost”, “admin”, “pass”);
if($test)
echo “success”;
else
die(“cannot connect maa…”);
?>
 Close connection using
mysql_close(connection_name)

MySQL (query)
 Select database: mysql_select_db(“database”,
connection);
 Run query: mysql_query(“SQL query);
<?php
$test = mysql_connect(“localhost”, “root”,””);
mysql_select_db(“data”, $test);
mysql_query(“Select * from table”);
?>
 SQL query: SELECT fieldname FROM tablename

MySQL (Display query)
 mysql_fetch_array($result)
 $result is array of data
 Example:
<?php
$result = mysql_query(“MySQL select
query”);
while($row = mysql_fetch_array($result)) {
echo $row[„fieldname‟];
}
?>

MySQL insert data
 SQL command: INSERT INTO table_name
(field1, field2, …) VALUES (value1, value2, …)
 Example:
mysql_query("INSERT INTO Address (No, Road,
Postcode) VALUES (11, „Jalan 19/2C', 40000)");

MySQL update data
 SQL command: UPDATE table_name SET
field1=value1, field2=value2,... WHERE
field=some_value
 Example:
mysql_query(“UPDATE Address SET
Postcode=40900 WHERE No=13");

MySQL delete data
 SQL command: DELETE FROM table_name
WHERE some_column = some_value
 Example:
mysql_query(“DELETE from Address WHERE
Postcode=40900");

Php & my sql

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Php & my sql