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我有一个类Database和类User。我的问题是我想创建一个数据库的实例，并在我的课程中使用它。PHP：使用数据库类
类User只是其中之一。我希望能够使用数据库对象从表中获取用户记录。我不想在每个类中创建一个数据库变量，因为我将使用会话。有解决方案吗？
class Database
{
/*
* Edit the following variables
*/
private $db_host = 'localhost'; // Database Host
private $db_user = 'root'; // Username
private $db_pass = ''; // Password
private $db_name = 'researchportal'; // Database
/*
* End edit
*/
private $con = false; // Checks to see if the connection is active
private $result = array(); // Results that are returned from the query
/*
* Connects to the database, only one connection
* allowed
*/
public function connect()
{
if(!$this->con)
{
$myconn = @mysql_connect($this->db_host,$this->db_user,$this->db_pass);
if($myconn)
{
$seldb = @mysql_select_db($this->db_name,$myconn);
if($seldb)
{
$this->con = true;
return true;
}
else
{
return false;
}
}
else
{
return false;
}
}
else
{
return true;
}
}
/*
* Changes the new database, sets all current results
* to null
*/
public function setDatabase($name)
{
if($this->con)
{
if(@mysql_close())
{
$this->con = false;
$this->results = null;
$this->db_name = $name;
$this->connect();
}
}
}
/*
* Checks to see if the table exists when performing
* queries
*/
private function tableExists($table)
{
$tablesInDb = @mysql_query('SHOW TABLES FROM '.$this->db_name.' LIKE "'.$table.'"');
if($tablesInDb)
{
if(mysql_num_rows($tablesInDb)==1)
{
return true;
}
else
{
return false;
}
}
}
/*
* Selects information from the database.
* Required: table (the name of the table)
* Optional: rows (the columns requested, separated by commas)
* where (column = value as a string)
* order (column DIRECTION as a string)
*/
public function select($table, $rows = '*', $where = null, $order = null)
{
$q = 'SELECT '.$rows.' FROM '.$table;
if($where != null)
$q .= ' WHERE '.$where;
if($order != null)
$q .= ' ORDER BY '.$order;
$query = @mysql_query($q);
if($query)
{
$this->numResults = mysql_num_rows($query);
for($i = 0; $i < $this->numResults; $i++)
{
$r = mysql_fetch_array($query);
$key = array_keys($r);
for($x = 0; $x < count($key); $x++)
{
// Sanitizes keys so only alphavalues are allowed
if(!is_int($key[$x]))
{
if(mysql_num_rows($query) > 1)
$this->result[$i][$key[$x]] = $r[$key[$x]];
else if(mysql_num_rows($query) < 1)
$this->result = null;
else
$this->result[$key[$x]] = $r[$key[$x]];
}
}
}
return true;
}
else
{
return false;
}
}
/*
* Insert values into the table
* Required: table (the name of the table)
* values (the values to be inserted)
* Optional: rows (if values don't match the number of rows)
*/
public function insert($table,$values,$rows = null)
{
if($this->tableExists($table))
{
$insert = 'INSERT INTO '.$table;
if($rows != null)
{
$insert .= ' ('.$rows.')';
}
for($i = 0; $i < count($values); $i++)
{
if(is_string($values[$i]))
$values[$i] = '"'.$values[$i].'"';
}
$values = implode(',',$values);
$insert .= ' VALUES ('.$values.')';
$ins = @mysql_query($insert);
if($ins)
{
return true;
}
else
{
return false;
}
}
}
/*
* Deletes table or records where condition is true
* Required: table (the name of the table)
* Optional: where (condition [column = value])
*/
public function delete($table,$where = null)
{
if($this->tableExists($table))
{
if($where == null)
{
$delete = 'DELETE '.$table;
}
else
{
$delete = 'DELETE FROM '.$table.' WHERE '.$where;
}
$del = @mysql_query($delete);
if($del)
{
return true;
}
else
{
return false;
}
}
else
{
return false;
}
}
/*
* Updates the database with the values sent
* Required: table (the name of the table to be updated
* rows (the rows/values in a key/value array
* where (the row/condition in an array (row,condition))
*/
public function update($table,$rows,$where)
{
if($this->tableExists($table))
{
// Parse the where values
// even values (including 0) contain the where rows
// odd values contain the clauses for the row
for($i = 0; $i < count($where); $i++)
{
if($i%2 != 0)
{
if(is_string($where[$i]))
{
if(($i+1) != null)
$where[$i] = '"'.$where[$i].'" AND ';
else
$where[$i] = '"'.$where[$i].'"';
}
}
}
$where = implode('',$where);
$update = 'UPDATE '.$table.' SET ';
$keys = array_keys($rows);
for($i = 0; $i < count($rows); $i++)
{
if(is_string($rows[$keys[$i]]))
{
$update .= $keys[$i].'="'.$rows[$keys[$i]].'"';
}
else
{
$update .= $keys[$i].'='.$rows[$keys[$i]];
}
// Parse to add commas
if($i != count($rows)-1)
{
$update .= ',';
}
}
$update .= ' WHERE '.$where;
$query = @mysql_query($update);
if($query)
{
return true;
}
else
{
return false;
}
}
else
{
return false;
}
}
/*
* Returns the result set
*/
public function getResult()
{
return $this->result;
}
}
类用户：
<?php
require_once 'class.database.php';
class User{
public $usr_id;
public $usr_name;
public $usr_level;
public $last_access_login;
public function __construct($id) {
$this->usr_id = $id;
//$this->usr_name = $usr_name;
//$this->usr_level = $usr_level;
$this->last_access_login = date("F d Y H:i:s.",time());
}
public function getUser()
{
// $db->select('login_users','*','user_id='.$this->usr_id.'');
// $res = $db->getResult();
// print_r($res);
$this->usr_name = $res['username'];
$this->usr_level = $res['user_level'];
$this->last_access_login = date("F d Y H:i:s.",time());
}
}
$a = new User(3);
$a->getUser();
?>
请不要略过基本解释，因为SO的90％的流量来自搜索引擎。有人在寻找这个问题可能需要这些细节。 –
没问题，你完全正确，加上 –
'private static $ staticInstance = NULL;'not'private static $ staticInstance = NULL：'Typo – SupaOden