A PHP database connection class_PHP tutorial

This article provides two database tutorial connection examples, mainly about data-related operations of the PHP tutorial and the MySQL tutorial. Friends in need can use it.

class mysql {
private $db_host; //Host address
private $db_user; //Username
private $db_pass; //Connection password
private $db_name; //name
private $db_charset; //Encoding
private $conn;
public $debug=false;//Debug switch, turned off by default
private $query_id; //Used to determine whether the sql statement is executed successfully
private $result; //result set
private $num_rows; //The number of rows in the result set, only valid for select
private $insert_id; //The id generated by the previous insert operation
// Constructor/Destructor
function __construct ($db_host,$db_user,$db_pass,$db_name,$db_charset,$conn) {
$this->db_host = $db_host ;
$this->db_user = $db_user ;
$this->db_pass = $db_pass ;
$this->db_name = $db_name ;
$this->db_charset = $db_charset;
$this->conn = $conn ;
$this->connect();
}
function __destruct () {
@mysql_close($this->conn);
}
// Connect/select database
public function connect () {
if ($this->conn == 'pconn') {
@$this->conn = mysql_pconnect($this->db_host,$this->db_user,$this->db_pass);
} else {
@$this->conn = mysql_connect($this->db_host,$this->db_user,$this->db_pass);
}
if (!$this->conn) {
$this->show_error('Database-Connection failed: Wrong username or password!');
}
if (!@mysql_select_db($this->db_name,$this->conn)) {
$this->show_error("Database-selection failed: Database $this->db_name is not available");
}
mysql_query("set names $this->db_charset");
return $this->conn;
}
// query method
public function query ($sql) {
if ($this->query_id) $this->free_result();
$this->query_id = @mysql_query($sql,$this->conn);
if (!$this->query_id) $this->show_error("sql statement "$sql" encountered an error during execution");
return $this->query_id;
}
// Display detailed error information
public function show_error ($msg) {
if($this->debug){
$errinfo = mysql_error();
echo "Error: $msg
Return: $errinfo

";
}else{
echo '

An error occurred!

';
}
}
// Get information about the success or failure of query execution
public function get_query_info($info){
if ($this->query_id) {
echo $info;
}
}
// Query all
public function findall ($table_name) {
$this->query("select * from $table_name");
}
// mysql_fetch_array
public function fetch_array () {
if ($this->query_id) {
$this->result = mysql_fetch_array($this->query_id);
return $this->result;
}
}
//......
public function fetch_assoc () {
if ($this->query_id) {
$this->result = mysql_fetch_assoc($this->query_id);
return $this->result;
}
}
public function fetch_row () {
if ($this->query_id) {
$this->result = mysql_fetch_row($this->query_id);
return $this->result;
}
}
public function fetch_object () {
if ($this->query_id) {
$this->result = mysql_fetch_object($this->query_id);
return $this->result;
}
}
// Get num_rows
public function num_rows () {
if ($this->query_id) {
$this->num_rows = mysql_num_rows($this->query_id);
return $this->num_rows;
}
}
// Get insert_id
public function insert_id () {
return $this->insert_id = mysql_insert_id();
}
//Show how many tables there are
public function show_tables () {
$this->query("show tables");
if ($this->query_id) {
echo "Database $this->db_name has ".$this->num_rows($this->query_id)." tables
";
$i = 1;
while ($row = $this->fetch_array($this->query_id)){
echo "$i -- $row[0]
";
$i++;
}
}
}
// Show how many databases there are in total
public function show_dbs(){
$this->query("show databases");
if ($this->query_id) {
echo "There are total databases ".$this->num_rows($this->query_id)."
";
$i = 1;
while ($this->row = $this->fetch_array($this->query_id)){
echo "$i -- ".$this->row[database]."
";
$i++;
}
}
}
//Delete database: return deletion result
public function drop_db ($db_name='') {
if ($db_name == '') {
$db_name = $this->db_name;//Delete the current database by default
$this->query("drop database $db_name");
}else {
$this->query("drop database $db_name");
}
if ($this->query_id) {
return "Database $db_name deleted successfully";
}else {
$this->show_error("Database $db_name deletion failed");
}
}
//Delete data table: return deletion result
public function drop_table ($table_name) {
$this->query("drop table $table_name");
if ($this->query_id) {
return "Data table $table_name deleted successfully";
}else {
$this->show_error("Deletion of data table $table_name failed");
}
}
//Create database
public function create_db ($db_name) {
$this->query("create database $db_name");
if($this->query_id){
return "Database $db_name created successfully";
}else {
$this->show_error("Database $db_name creation failed");
}
}
// Get database version
public function get_info(){
echo mysql_get_server_info();
}
// Release memory
public function free_result () {
if ( @mysql_free_result($this->query_id) )
unset ($this->result);
$this->query_id = 0;
}
} // end class
?>

The following provides an automatic selection database remote or local connection code

// Contains mysql operation class
include_once 'mysql.class.php';
// Local mysql data
$mysql_local_data = array('db_host'=>'localhost',
'db_user'=>'root',
'db_pass'=>'root',
'db_name'=>'test');
//Remote mysql data
$mysql_remote_data = array('db_host'=>'61.183.41.178',
'db_user'=>'xxx',
'db_pass'=>'xxx',
'db_name'=>'xxx');
// Public data
$tb_prefix = 'php95_';
$db_charset = 'utf-8';
//If the local connection is successful, instantiate the local mysql class, otherwise connect to the remote database and instantiate the mysql class
if (@mysql_connect($mysql_local_data[db_host], $mysql_local_data[db_user], $mysql_local_data[db_pass]))
$db = new mysql($db_host, $mysql_local_data[db_user], $mysql_local_data[db_pass], $mysql_local_data[db_name], $db_charset, $conn);
else
$db = new mysql($mysql_remote_data[db_host], $mysql_remote_data[db_user], $mysql_remote_data[db_pass], $mysql_remote_data[db_name], $db_charset, $conn);
$db->show_tables(); //Test: display all table names under the current database
?>

Suppose we want to operate the database of the virtual host in the test.php file, we must first debug locally, then we must connect to two different databases, local and remote. Question: How to make test.php automatically recognize the current connection? Local or remote database?