Connecting_to_Database(MySQL)_in_PHP (3).pdf

Connecting to Database(MySQL) in
PHP
Presented by
AR ARIPUNISHABEE
ASSISTANT PROFESSOR IN COMPUTER SCIENCE

Create a Connection with
DB:
• By using PHP,we can able to connect with database(MySQL).
• In order to connect with database, we need three
parameters
⮚Hostname(ServerName)
⮚Username
⮚Password
(By default “localhost”)
(By default “root”)
(By default “No
Password”)
• In PHP, we have one inbuilt function to create connection with database(MySQL)
.i.e.,
– mysqli_connect(hostname,username,password)
• This function creates a successful connection with DB if you provide valid
information.
• When the connection is not well we can kill that connection by using
– die(“Can’t create connection”);
• mysqli_close() function is used to disconnect with MySQL database.

Example:
<?php
$host = 'localhost';
$user = 'root';
$pass = '';
$conn = mysqli_connect($host, $user,
$pass); if(! $conn )
{
die('Could not connect: ' . mysqli_error());
}
echo 'Connected successfully';
mysqli_close($conn);
?>

Execute Queries:
Create a Database:
• After creating connection we need to create a database .
• PHP has one in built function to perform different operations
(create (db &table),insert,update and delete) on
database.i.e., – mysqli_query(connection,query)
• It has two parameters, those are
– Connection :name of the connection
– Query: specifies the query

Example:
<?php
$user = 'root';
$pass = '';
$pass); if(! $conn )
{
}
$sql = 'CREATE DATABASE
CollegeDb'; if(mysqli_query(
$conn,$sql))
{
echo "Database created successfully.";
}
else
{
echo "Sorry, database creation failed
".mysqli_error($conn);
}

Creating a
Table
• After creating database, we need to
create table.
• In PHP, mysqli_query() function is used
to create a table.

Example
<?php
$user = 'root';
$pass = '';
$dbname='CollegeDb';
$pass,$dbname); if(! $conn )
{
}
echo "Connected successfully “;
$sql = "create table students(Sid INT,Sname VARCHAR(20),Age
INT)"; if(mysqli_query($conn, $sql)){
echo "Table students created successfully";
}else{
echo "Could not create table: ". mysqli_error($conn);
}
?>

Insert Record into
Table
• After creating table, we need to
insert data(records) into table.
• In PHP, mysqli_query() function is used
to insert record into table.

Example
<?php
$user = 'root';
$pass = '';
$pass,$dbname); if(! $conn )
{
}
echo 'Connected successfully‘;
$sql = 'INSERT INTO students VALUES (521,"Madhu",
30)'; if(mysqli_query($conn, $sql)){
echo "Record inserted successfully";
}else{
echo "Could not insert record: ". mysqli_error($conn);
}
?>

Delete
Record
<?php
$user = 'root';
$pass = '';
$pass,$dbname);
if(! $conn )
{
}
echo 'Connected successfully‘;
$id=521;
$sql = “delete from students where sid=$id" ;
if(mysqli_query($conn, $sql)){
echo "Record inserted successfully";
}else{
echo "Could not insert record: ". mysqli_error($conn);
}
?>

Select data from
Table
• In PHP, mysqli_query() function is used to
retrieve data from table.
• There are two other MySQLi functions
used in select query.
$result):
returns
– mysqli_num_rows(mysqli_result
number of rows.
– mysqli_fetch_assoc(mysqli_resul
t
$result):
returns
row as an associative array. Each key of the array
represents the column name of the table. It return
NULL if there are no more rows.

Example:
$sql = 'SELECT * FROM students';
$retval=mysqli_query($conn, $sql);
if(mysqli_num_rows($retval) > 0)
{
while($row = mysqli_fetch_assoc($retval))
{
echo "Student ID :".$row['sid']." ";
echo "Student NAME :". $row['sname']." 
"; echo "Student Age :". $row['age']." ";
echo " ";
} //end of while
}
else
{
echo "0 results";
}

Connecting_to_Database(MySQL)_in_PHP (3).pdf

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