3 php-connect-to-my sql

Sri Lanka-German Training InstituteDepartment of Information and Communication Technology
National Diploma in Information and Communication Technology
PHP :3-PHP-CONNECT-TO-MySQL>
K72C001M07 - Web Programming
Y. Achchuthan
Department of Information & Communication Technology,
Sri Lanka – German Training Institute
11/23/2018 3-PHP-CONNECT-TO-MySQL 1

What is MySQL?
• MySQL is a database system used on the web
• MySQL is a database system that runs on a server
• MySQL is ideal for both small and large applications
• MySQL is very fast, reliable, and easy to use
• MySQL uses standard SQL
• MySQL compiles on a number of platforms
• MySQL is free to download and use
• MySQL is developed, distributed, and supported by Oracle
Corporation

Connect to MySQL
• Open a Connection to MySQL
• Syantax
$con = mysqli_connect(host,username,password,dbname,port,socket);
Return Value: Returns an object representing the connection to the MySQL
server
Parameter Description
host Optional. Specifies a host name or an IP address
username Optional. Specifies the MySQL username
password Optional. Specifies the MySQL password
dbname Optional. Specifies the default database to be used
port Optional. Specifies the port number to attempt to connect to the MySQL
server
socket Optional. Specifies the socket or named pipe to be used

Closing a Connection
• Close the created database connection as follows
mysql_close($con);

Example - mysqli_connect()
//config.php
define('DB_HOST','localhost');
define('DB_USER','root');
define('DB_PASS','');
define('DB_NAME','');
$conn=mysqli_connect(DB_HOST,DB_USER,DB_PASS,DB_NAME)
;
if (mysqli_connect_errno()){
echo "Failed to connect to MySQL: " .
mysqli_connect_error();
}
echo "Connected successfully";

mysqli_query() Function
• Perform queries against the database:
• Syntax
mysqli_query(connection,query,resultmode);
Parameter Description
connection Required. Specifies the MySQL connection to use
query Required. Specifies the query string
resultmode Optional. A constant. Either:
•MYSQLI_USE_RESULT (Use this if we have to retrieve large amount of
data)
•MYSQLI_STORE_RESULT (This is default)

Create a MySQL Database
$sql = "CREATE DATABASE NVQ5";
if (mysqli_query($conn, $sql)) {
echo "Database created successfully";
} else {
echo "Error creating database: " .
mysqli_error($conn);
}

Create MySQL Tables
$sql = "CREATE TABLE MyGuests (
id INT(6) UNSIGNED AUTO_INCREMENT PRIMARY KEY,
firstname VARCHAR(30) NOT NULL,
lastname VARCHAR(30) NOT NULL,
email VARCHAR(50),
reg_date TIMESTAMP
)";
echo "Table MyGuests created successfully";
} else {
echo "Error creating table: " .
}

Notes on the table above
• NOT NULL - Each row must contain a value for that column, null
values are not allowed
• DEFAULT value - Set a default value that is added when no other
value is passed
• UNSIGNED - Used for number types, limits the stored data to positive
numbers and zero
• AUTO INCREMENT - MySQL automatically increases the value of the
field by 1 each time a new record is added
• PRIMARY KEY - Used to uniquely identify the rows in a table. The
column with PRIMARY KEY setting is often an ID number, and is often
used with AUTO_INCREMENT

Insert Data Into MySQL
After a database and a table have been created, we can start adding
data in them.
• Here are some syntax rules to follow:
• The SQL query must be quoted in PHP
• String values inside the SQL query must be quoted
• Numeric values must not be quoted
• The word NULL must not be quoted
Note: I f a column is AUTO_INCREMENT (like the "id" column) or
TIMESTAMP (like the "reg_date" column), it is no need to be specified
in the SQL query; MySQL will automatically add the value.

Insert Data Into MySQL
$sql = "INSERT INTO MyGuests (firstname,
lastname, email) VALUES ('John', 'Doe',
'john@example.com')";
echo "New record created successfully";
} else {
echo "Error: " . $sql . "<br>" .
}

Insert Multiple Records Into MySQL
$sql = "INSERT INTO MyGuests (firstname, lastname,
email)
VALUES ('John', 'Doe', 'john@example.com');";
$sql .= "INSERT INTO MyGuests (firstname,
lastname,email)
VALUES ('Mary', 'Moe', 'mary@example.com');";
$sql .= "INSERT INTO MyGuests (firstname,
lastname,email)
VALUES ('Julie', 'Dooley', 'julie@example.com')";
if (mysqli_multi_query($conn, $sql)) {
echo "New records created successfully";
} else {
echo "Error: " . $sql . "<br>" . mysqli_error($conn);
}

Select Data From a MySQL
$sql = "SELECT * FROM MyGuests";
//$sql = "SELECT id, firstname, lastname FROM MyGuests";
$result = mysqli_query($conn, $sql);
if (mysqli_num_rows($result) > 0) {
// output data of each row
while($row = mysqli_fetch_assoc($result)) {
//var_dump($row);
echo "id: " . $row["id"]. " - Name: " .
$row["firstname"]. " " . $row["lastname"]. "<br>";
}
} else {
echo "0 results";
}

Delete Data From a MySQL
$sql = "DELETE FROM MyGuests WHERE id=3";
echo "Record deleted successfully";
} else {
echo "Error deleting record: " .
}

Update Data In a MySQL
$sql = "UPDATE MyGuests SET lastname='Mugund'
WHERE id=9";
echo "Record updated successfully";
} else {
echo "Error updating record: " .
}

Limit Data Selections From a MySQL
$sql = "SELECT * FROM MyGuests ORDER BY id ASC LIMIT
10 OFFSET 15";
//$sql = "SELECT * FROM MyGuests ORDER BY id ASC
LIMIT 10 OFFSET 10";
$result = mysqli_query($conn, $sql);
if (mysqli_num_rows($result) > 0) {
while($row = mysqli_fetch_assoc($result)) {
echo "id: " . $row["id"]. " - Name: " .
$row["firstname"]. " " . $row["lastname"].
"<br>";
}
} else {
echo "0 results";
}
Note: The SQL query above says "return only 10 records, start on record 16 (OFFSET 15)":

Reference
www.w3schools.com
www.php.net
www.slgti.com
Friday, November 23, 2018 17

3 php-connect-to-my sql

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