Basic operation of PHP database

<?php

Connecting to a database
/* $con =mysql_connect ("localhost", "root", "19960621");/or Die (' Error: '. mysql_error ());
if (! $con) {
Die ("Connection failed!". Mysql_errno ());
}else{
echo "Connection to database Success";
mysql_query ("CREATE DATABASE dbmysql", $con);
mysql_select_db ("Dbmysql", $con);
$sql = "CREATE TABLE person" (PersonID int not NULL auto_increment,firstname varchar (), LastName varchar (+), age int, PRIMARY KEY (PersonID)) ";
$str =mysql_query ($sql, $con);
echo "<br>". $str. " <br> ";
Mysql_close ($con);
}
Inserting data into the table
$con =mysql_connect ("localhost", "root", "19960621");
mysql_select_db ("Dbmysql", $con);
mysql_query ("INSERT into person (' FirstName ', ' LastName ', ' age ') VALUES (' Tom ', ' Tony ', ' 20 ')");
mysql_query ("INSERT into person (' FirstName ', ' LastName ', ' age ') VALUES (' LH ', ' h ', ' 16 ')");
mysql_query ("INSERT into person (' FirstName ', ' LastName ', ' age ') VALUES (' Jy ', ' j ', ' 24 ')");
Querying data
$con =mysql_connect ("localhost", "root", "19960621");
mysql_select_db ("Dbmysql", $con);
$result =mysql_query ("SELECT * from person");
while ($row =mysql_fetch_array ($result)) {
echo $row ["FirstName"]. "". $row ["LastName"];
echo "<br>";
}
Update data
$con =mysql_connect ("localhost", "root", "19960621");
mysql_select_db ("Dbmysql", $con);
mysql_query ("Update person set firstname= ' dx ', lastname= ' x ', ' age ' =18 where ' personID ' = 3");
Delete data
$con =mysql_connect ("localhost", "root", "19960621");
mysql_select_db ("Dbmysql", $con);
mysql_query ("Delete from person where ' personID ' = 2");
Mysql_close ($con);

Mysql_list_dbs () function ==> lists all databases in the MySQL server
$con =mysql_connect ("localhost", "root", "19960621");
$dl =mysql_list_dbs ($con);
while ($db =mysql_fetch_object ($DL)) {
echo $db->database. " <br> ";
}
Mysql_close ($con);
Mysql_num_fields () function ==> returns the number of fields in the result set
$con = mysql_connect ("localhost", "root", "19960621");
if (! $con) {
Die (' Could not connect: '. Mysql_error ());
}
$db _selected = mysql_select_db ("Dbmysql", $con);
$sql = "SELECT * from person";
$result = mysql_query ($sql, $con);
echo Mysql_num_fields ($result);//number of output columns
Mysql_close ($con);
Mysql_num_rows () function ==> returns the number of rows in the result set
$con = mysql_connect ("localhost", "root", "19960621");
if (! $con) {
Die (' Could not connect: '. Mysql_error ());
}
$db _selected = mysql_select_db ("Dbmysql", $con);
$sql = "SELECT * from person";
$result = mysql_query ($sql, $con);
echo mysql_num_rows ($result);//Total number of rows queried
Mysql_close ($con);
Mysql_affected_rows () function ==> returns the number of record rows affected by the previous MySQL operation
$con = mysql_connect ("localhost", "root", "19960621");
if (! $con) {
Die (' Could not connect: '. Mysql_error ());
}
mysql_select_db ("Dbmysql");
mysql_query ("DELETE from person WHERE PersonID = 3");
$RC = Mysql_affected_rows ();
echo "Records deleted:". $RC;
Mysql_close ($con);
Mysql_real_escape_string () function ==> escape special characters in strings used in SQL statements
Code to get the user name and password
$user = "A\R\NBC";
$pwd = "A\R\NBC";
Escape the user name for use in SQL
$user = mysql_real_escape_string ($user);
$pwd = ($PWD);
$sql = "SELECT * from Users WHERE user= '". $user. "' and password= '". $pwd. "‘";
Echo $sql; User name and password comparison
The mysql_result () function returns the value of a field in the result set
$con = mysql_connect ("localhost", "root", "19960621");
if (! $con) {
Die (' Could not connect: '. Mysql_error ());
}
$db _selected = mysql_select_db ("Dbmysql", $con);
$sql = "SELECT * from person";
$result = mysql_query ($sql, $con);
echo mysql_result ($result);
Mysql_close ($con); * *

Basic operation of PHP database