Category: Database

Install Mysql 8 – Centos 8

sudo yum update
sudo yum install mysql-server mysql -y
sudo systemctl enable mysqld
sudo systemctl start mysqld

Now we need to set root password

mysql_secure_installation
 
Securing the MySQL server deployment.
 
Connecting to MySQL using a blank password.
 
VALIDATE PASSWORD COMPONENT can be used to test passwords
and improve security. It checks the strength of password
and allows the users to set only those passwords which are
secure enough. Would you like to setup VALIDATE PASSWORD component?
 
Press y|Y for Yes, any other key for No: n
Please set the password for root here.
 
New password:
 
Re-enter new password:
By default, a MySQL installation has an anonymous user,
allowing anyone to log into MySQL without having to have
a user account created for them. This is intended only for
testing, and to make the installation go a bit smoother.
You should remove them before moving into a production
environment.
 
Remove anonymous users? (Press y|Y for Yes, any other key for No) : y
Success.
 
 
Normally, root should only be allowed to connect from
'localhost'. This ensures that someone cannot guess at
the root password from the network.
 
Disallow root login remotely? (Press y|Y for Yes, any other key for No) : y
Success.
 
By default, MySQL comes with a database named 'test' that
anyone can access. This is also intended only for testing,
and should be removed before moving into a production
environment.
 
 
Remove test database and access to it? (Press y|Y for Yes, any other key for No) : y
- Dropping test database...
Success.
 
- Removing privileges on test database...
Success.
 
Reloading the privilege tables will ensure that all changes
made so far will take effect immediately.
 
Reload privilege tables now? (Press y|Y for Yes, any other key for No) : y
Success.
 
All done!

Support legacy auth methods

sudo nano /etc/my.cnf

Add at the bottom of the file

 default-authentication-plugin=mysql_native_password

Restart mysql server and done!

sudo systemctl restart mysqld

InfluxDB PHP

Install Influxdb, and start it. After start we should create user After we should edit influx config file on CentOS /etc/influxdb/influxdb.conf Find and replace volumes in http section restart influx db Now in php to insert data

$q = "test,city=".$city." population=87879879 \n";
 
$ch = curl_init();
 
curl_setopt($ch, CURLOPT_URL, "http://127.0.0.1:8086/write?db=databasename&u=username&p=password");
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
curl_setopt($ch, CURLOPT_POSTFIELDS, substr($q, 0, -1));
curl_setopt($ch, CURLOPT_POST, 1);
 
$headers = array();
$headers[] = "Content-Type: application/x-www-form-urlencoded";
curl_setopt($ch, CURLOPT_HTTPHEADER, $headers);
 
$result = curl_exec($ch);
if (curl_errno($ch)) {
echo 'Error:' . curl_error($ch);
}
curl_close($ch);

To read data from database

$query = "<strong>SELECT * FROM test</strong>";
 
$ch = curl_init();
$query = urlencode($q);
curl_setopt($ch, CURLOPT_URL, "http://localhost:8086/query?db=database&amp;u=username&amp;p=password&amp;q=" . $query);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
curl_setopt($ch, CURLOPT_POST, 0);
 
$headers = array();
$headers[] = "Content-Type: application/x-www-form-urlencoded";
curl_setopt($ch, CURLOPT_HTTPHEADER, $headers);
 
$result = curl_exec($ch);
if (curl_errno($ch)) {
echo 'Error:' . curl_error($ch);
}
curl_close($ch);
 
//display array
print_r(json_decode($result, true));

make sure you have changed database,username,password

Delete Duplicate Rows In Mysql With PHP

$dupq = mysql_query("SELECT * FROM `db`");
$dups = mysql_fetch_array($dupq);
foreach($dups as $dup){
mysql_query("DELETE FROM db WHERE duplicate_COLUMN='".$dup['duplicate_column']."' AND id!='".$dup['id']."'");
}

duplicate_COLUMN – Name of column and $dup[‘column_name’] delete duplicates which include same column data.