Php modul-3

What is Database?
● A database is an organized collection of
data.
● The data collection are typically organized
to model relevant aspects of reality in a
way that supports processes requiring this
information

What is Database Management
System?
● Database management systems (DBMSs) are
specially designed applications that interact
with the user, other applications, and the
database itself to capture and analyze data.
● A general-purpose database management
system (DBMS) is a software system designed
to allow the definition, creation, querying,
update, and administration of databases.

Why use database?
● Databases are most useful when it comes
to storing information that fits into logical
categories.
● Example: store employees record
– Supervisors table, managers tables, suppliers
table, etc.

Why MySQL?
● The most popular database system used with PHP.
● PHP combined with MySQL are cross-platform (you
can develop in Windows and serve on a Unix platform)
● Most web hosts do not allow you to create a database
directly through a PHP script.
● Instead they require that you use the PHP/MySQL
administration tools on the web host control panel to
create these databases

What is “Queries”
● A query is a question or a request.
● We can query a database for specific
information and have a recordset returned
● Example:
– SELECT * FROM customers;

How to learn SQL
● Remember this:
– SQL language is not complicated
● There are many keywords in MySQL, and a
good programming habit when using ANY of
these words is to capitalize them.
● This helps draw them out from the rest of the
code and makes them much easier to read.
● Example:
– SELECT * FROM example

SQL Basic Command
● Create Database
– CREATE DATABASE <database_name>
● Use Database
– Use <database_name>
● Create Table
– CREATE TABLE <table_name> (col1 type1, col2 type2, … , colx
typex)
● Example
– CREATE DATABASE exercise;
– Use exercise;
– CREATE TABLE student (name varchar(30), age INT);

SQL Basic Command
● Insert data to table
– INSERT INTO <table_name> (col1,col2, … , colx)
VALUES (val1, val2, … , valx);
– Example:
● INSERT INTO student VALUES ('William',27);
● Query data from table
– SELECT <colx| *> FROM <table_name> WHERE
<expression>
– Example:
● SELECT name FROM student WHERE age>20;

SQL Basic Command
● Edit data
– UPDATE <table_name> SET <colx=valx> WHERE
<expression>
● Delete data
– DELETE FROM <table_name> WHERE <expression>
● Example
– UPDATE student SET age=30 WHERE
name='William';
– DELETE FROM student WHERE name='William';

PHP Form Handling
● Use $_GET or $_POST to handle the data from the form
● Example (form_get.html)
<html>
<body>
<form action="helloget.php" method="get">
Name: <input type="text" name="name"><br>
<input type="submit">
</form>
</body>
</html>

PHP Form Handling
● Helloget.php
<html>
<body>
Welcome <?php echo $_GET["name"]; ?>
</body>
</html>

PHP Form Handling
● (form_post.html)
<html>
<body>
<form action="hellopost.php" method="post">
Name: <input type="text" name="name"><br>
<input type="submit">
</form>
</body>
</html>

PHP Form Handling
● Hellopost.php
<html>
<body>
Welcome <?php echo $_POST["name"]; ?>
</body>
</html>

PHP Form Handling
● GET vs. POST
– $_GET is an array of variables passed to the
current script via the URL parameters.
– $_POST is an array of variables passed to the
current script via the HTTP POST method.

PHP Form Handling
● When we use GET method?
– Remember this : Information sent from a form
with the GET method is visible to everyone
(in address bar).
– GET has limits on the amount of information
to send (only 2000 character).
– ONLY USED for sending non-sensitive data.
– Never use GET to send sensitive informations
such as username or password

PHP Form Handling
● When we use POST method?
– Remember this : Information sent from a form
with the POST method is invisible to others.
– POST has no limits on the amount of
information to send.
– Supports advanced functionality such as multi-
part binary input while uploading files to
server.

PHP & MySQL
● Open connection to MySQL
– mysqli_connect(host, username, password,
database_name)
– Example
$con=mysqli_connect(“localhost”,”root”,”1234”,”exercis
e”);
● Check connection
if (mysqli_connect_errno($con))
echo "Failed to connect to MySQL: " .
mysqli_connect_error();

PHP and MySQL
● Close connection
– mysqli_close(connection_variable)
● Example
– mysqli_close($con);

PHP and MySQL
● Send query to MySQL
– mysqli_query(<query>,<connection_variable>
);
● Example:
$sql=”INSERT INTO student
VALUES('John',33)”;
mysqli_query($sql,$con);

PHP and MySQL
● Retrieve result of query
$sql=”SELECT * FROM student”;
$result=mysqli_query($sql,$con);
While ($row = mysqli_fetch_array($result)) {
echo $row['name'] . “ “ . $row['age'] . “<br>”;
}

excercise
● A. Database
– Use database exercise
– Create a course table which have structure like this:
● id_course – varchar
● name_course – varchar
● Credit – int
– Create a student table which have structure like this:
● id_student – varchar
● Firstname – varchar
● Lastname - varchar
– Insert 10 data into table course and student

excercise
● B. PHP and MySQL
– Create a web application with php to handles
● The input for table course and student
● List all data for table course and student
● Search data for table course and student

Home Works
● Create a web applications with PHP to
handle the update and delete proses for
table course and student

Php modul-3

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