PHP5 PDO Singleton Class

sickcat2004

http://tonylandis.com/php/php5-pdo-singleton-class/

1. $dbObj =& new sdb("mysql:host=localhost;dbname=testdb", 'username', 'password');

1. <?php
   
2. 
   
3. /**
   
4.  * PDO SINGLETON CLASS
   
5.  *
   
6.  * @author Tony Landis
   
7.  * @link http://www.tonylandis.com
   
8.  * @license Use how you like it, just please don't remove or alter this PHPDoc
   
9.  */
   
10. class sdb
    
11. {
    
12.     /**
    
13.      * The singleton instance
    
14.      *
    
15.      */
    
16.     static private $PDOInstance;
    
17.      
    
18.       /**
    
19.        * Creates a PDO instance representing a connection to a database and makes the instance available as a singleton
    
20.        *
    
21.        * @param string $dsn The full DSN, eg: mysql:host=localhost;dbname=testdb
    
22.        * @param string $username The user name for the DSN string. This parameter is optional for some PDO drivers.
    
23.        * @param string $password The password for the DSN string. This parameter is optional for some PDO drivers.
    
24.        * @param array $driver_options A key=>value array of driver-specific connection options
    
25.        *
    
26.        * @return PDO
    
27.        */
    
28.     public function __construct($dsn, $username=false, $password=false, $driver_options=false)
    
29.     {
    
30.         if(!self::$PDOInstance) {
    
31.      try {
    
32.              self::$PDOInstance = new PDO($dsn, $username, $password, $driver_options);
    
33.             } catch (PDOException $e) {
    
34.              die("PDO CONNECTION ERROR: " . $e->getMessage() . "<br/>");
    
35.             }
    
36.         }
    
37.           return self::$PDOInstance;          
    
38.     }
    
39.     
    
40.       /**
    
41.        * Initiates a transaction
    
42.        *
    
43.        * @return bool
    
44.        */
    
45.     public function beginTransaction() {
    
46.         return self::$PDOInstance->beginTransaction();
    
47.     }
    
48.         
    
49.     /**
    
50.      * Commits a transaction
    
51.      *
    
52.      * @return bool
    
53.      */
    
54.     public function commit() {
    
55.         return self::$PDOInstance->commit();
    
56.     }
    
57.     
    
58.     /**
    
59.      * Fetch the SQLSTATE associated with the last operation on the database handle
    
60.      *
    
61.      * @return string
    
62.      */
    
63.     public function errorCode() {
    
64.         return self::$PDOInstance->errorCode();
    
65.     }
    
66.     
    
67.     /**
    
68.      * Fetch extended error information associated with the last operation on the database handle
    
69.      *
    
70.      * @return array
    
71.      */
    
72.     public function errorInfo() {
    
73.         return self::$PDOInstance->errorInfo();
    
74.     }
    
75.     
    
76.     /**
    
77.      * Execute an SQL statement and return the number of affected rows
    
78.      *
    
79.      * @param string $statement
    
80.      */
    
81.     public function exec($statement) {
    
82.         return self::$PDOInstance->exec($statement);
    
83.     }
    
84.     
    
85.     /**
    
86.      * Retrieve a database connection attribute
    
87.      *
    
88.      * @param int $attribute
    
89.      * @return mixed
    
90.      */
    
91.     public function getAttribute($attribute) {
    
92.         return self::$PDOInstance->getAttribute($attribute);
    
93.     }
    
94. 
    
95.     /**
    
96.      * Return an array of available PDO drivers
    
97.      *
    
98.      * @return array
    
99.      */
    
100.     public function getAvailableDrivers(){
     
101.         return Self::$PDOInstance->getAvailableDrivers();
     
102.     }
     
103.     
     
104.     /**
     
105.      * Returns the ID of the last inserted row or sequence value
     
106.      *
     
107.      * @param string $name Name of the sequence object from which the ID should be returned.
     
108.      * @return string
     
109.      */
     
110.     public function lastInsertId($name) {
     
111.         return self::$PDOInstance->lastInsertId($name);
     
112.     }
     
113.         
     
114.        /**
     
115.      * Prepares a statement for execution and returns a statement object
     
116.      *
     
117.      * @param string $statement A valid SQL statement for the target database server
     
118.      * @param array $driver_options Array of one or more key=>value pairs to set attribute values for the PDOStatement obj
     
119. returned
     
120.      * @return PDOStatement
     
121.      */
     
122.     public function prepare ($statement, $driver_options=false) {
     
123.         if(!$driver_options) $driver_options=array();
     
124.         return self::$PDOInstance->prepare($statement, $driver_options);
     
125.     }
     
126.     
     
127.     /**
     
128.      * Executes an SQL statement, returning a result set as a PDOStatement object
     
129.      *
     
130.      * @param string $statement
     
131.      * @return PDOStatement
     
132.      */
     
133.     public function query($statement) {
     
134.         return self::$PDOInstance->query($statement);
     
135.     }
     
136.     
     
137.     /**
     
138.      * Execute query and return all rows in assoc array
     
139.      *
     
140.      * @param string $statement
     
141.      * @return array
     
142.      */
     
143.     public function queryFetchAllAssoc($statement) {
     
144.         return self::$PDOInstance->query($statement)->fetchAll(PDO::FETCH_ASSOC);
     
145.     }
     
146.     
     
147.     /**
     
148.      * Execute query and return one row in assoc array
     
149.      *
     
150.      * @param string $statement
     
151.      * @return array
     
152.      */
     
153.     public function queryFetchRowAssoc($statement) {
     
154.         return self::$PDOInstance->query($statement)->fetch(PDO::FETCH_ASSOC);     
     
155.     }
     
156.     
     
157.     /**
     
158.      * Execute query and select one column only
     
159.      *
     
160.      * @param string $statement
     
161.      * @return mixed
     
162.      */
     
163.     public function queryFetchColAssoc($statement) {
     
164.         return self::$PDOInstance->query($statement)->fetchColumn();     
     
165.     }
     
166.     
     
167.     /**
     
168.      * Quotes a string for use in a query
     
169.      *
     
170.      * @param string $input
     
171.      * @param int $parameter_type
     
172.      * @return string
     
173.      */
     
174.     public function quote ($input, $parameter_type=0) {
     
175.         return self::$PDOInstance->quote($input, $parameter_type);
     
176.     }
     
177.     
     
178.     /**
     
179.      * Rolls back a transaction
     
180.      *
     
181.      * @return bool
     
182.      */
     
183.     public function rollBack() {
     
184.         return self::$PDOInstance->rollBack();
     
185.     }
     
186.     
     
187.     /**
     
188.      * Set an attribute
     
189.      *
     
190.      * @param int $attribute
     
191.      * @param mixed $value
     
192.      * @return bool
     
193.      */
     
194.     public function setAttribute($attribute, $value ) {
     
195.         return self::$PDOInstance->setAttribute($attribute, $value);
     
196.     }
     
197. }
     
198. ?>