PHP Data Objects
- Introduction
- Installing/Configuring
- Predefined Constants
- Connections and Connection management
- Transactions and auto-commit
- Prepared statements and stored procedures
- Errors and error handling
- Large Objects (LOBs)
- PDO — The PDO class
- PDO::beginTransaction — Initiates a transaction
- PDO::commit — Commits a transaction
- PDO::__construct — Creates a PDO instance representing a connection to a database
- PDO::errorCode — Fetch the SQLSTATE associated with the last operation on the database handle
- PDO::errorInfo — Fetch extended error information associated with the last operation on the database handle
- PDO::exec — Execute an SQL statement and return the number of affected rows
- PDO::getAttribute — Retrieve a database connection attribute
- PDO::getAvailableDrivers — Return an array of available PDO drivers
- PDO::inTransaction — Checks if inside a transaction
- PDO::lastInsertId — Returns the ID of the last inserted row or sequence value
- PDO::prepare — Prepares a statement for execution and returns a statement object
- PDO::query — Executes an SQL statement, returning a result set as a PDOStatement object
- PDO::quote — Quotes a string for use in a query.
- PDO::rollBack — Rolls back a transaction
- PDO::setAttribute — Set an attribute
- PDOStatement — The PDOStatement class
- PDOStatement::bindColumn — Bind a column to a PHP variable
- PDOStatement::bindParam — Binds a parameter to the specified variable name
- PDOStatement::bindValue — Binds a value to a parameter
- PDOStatement::closeCursor — Closes the cursor, enabling the statement to be executed again.
- PDOStatement::columnCount — Returns the number of columns in the result set
- PDOStatement::debugDumpParams — Dump an SQL prepared command
- PDOStatement::errorCode — Fetch the SQLSTATE associated with the last operation on the statement handle
- PDOStatement::errorInfo — Fetch extended error information associated with the last operation on the statement handle
- PDOStatement::execute — Executes a prepared statement
- PDOStatement::fetch — Fetches the next row from a result set
- PDOStatement::fetchAll — Returns an array containing all of the result set rows
- PDOStatement::fetchColumn — Returns a single column from the next row of a result set
- PDOStatement::fetchObject — Fetches the next row and returns it as an object.
- PDOStatement::getAttribute — Retrieve a statement attribute
- PDOStatement::getColumnMeta — Returns metadata for a column in a result set
- PDOStatement::nextRowset — Advances to the next rowset in a multi-rowset statement handle
- PDOStatement::rowCount — Returns the number of rows affected by the last SQL statement
- PDOStatement::setAttribute — Set a statement attribute
- PDOStatement::setFetchMode — Set the default fetch mode for this statement
- PDOException — The PDOException class
- PDO Drivers
- CUBRID (PDO) — CUBRID Functions (PDO_CUBRID)
- MS SQL Server (PDO) — Microsoft SQL Server and Sybase Functions (PDO_DBLIB)
- Firebird (PDO) — Firebird Functions (PDO_FIREBIRD)
- IBM (PDO) — IBM Functions (PDO_IBM)
- Informix (PDO) — Informix Functions (PDO_INFORMIX)
- MySQL (PDO) — MySQL Functions (PDO_MYSQL)
- MS SQL Server (PDO) — Microsoft SQL Server Functions (PDO_SQLSRV)
- Oracle (PDO) — Oracle Functions (PDO_OCI)
- ODBC and DB2 (PDO) — ODBC and DB2 Functions (PDO_ODBC)
- PostgreSQL (PDO) — PostgreSQL Functions (PDO_PGSQL)
- SQLite (PDO) — SQLite Functions (PDO_SQLITE)
- 4D (PDO) — 4D Functions (PDO_4D)
Коментарии
Below is an example of extending PDO & PDOStatement classes:
<?php
class Database extends PDO
{
function __construct()
{
parent::__construct('mysql:dbname=test;host=localhost', 'root', '');
$this->setAttribute(PDO::ATTR_STATEMENT_CLASS, array('DBStatement', array($this)));
}
}
class DBStatement extends PDOStatement
{
public $dbh;
protected function __construct($dbh)
{
$this->dbh = $dbh;
$this->setFetchMode(PDO::FETCH_OBJ);
}
public function foundRows()
{
$rows = $this->dbh->prepare('SELECT found_rows() AS rows', array(PDO::MYSQL_ATTR_USE_BUFFERED_QUERY => TRUE));
$rows->execute();
$rowsCount = $rows->fetch(PDO::FETCH_OBJ)->rows;
$rows->closeCursor();
return $rowsCount;
}
}
?>
I wanted to extend PDO class to store statistics of DB usage, and I faced some problems. I wanted to count number of created statements and number of their executings. So PDOStatement should have link to PDO that created it and stores the statistical info. The problem was that I didn't knew how PDO creates PDOStatement (constructor parameters and so on), so I have created these two classes:
<?php
/**
* PHP Document Object plus
*
* PHP Document Object plus is library with functionality of PDO, entirely written
* in PHP, so that developer can easily extend it's classes with specific functionality,
* such as providing database usage statistics implemented in v1.0b
*
* @author Peter Pokojny
* @license http://opensource.org/licenses/gpl-license.php GNU Public License
*/
class PDOp {
protected $PDO;
public $numExecutes;
public $numStatements;
public function __construct($dsn, $user=NULL, $pass=NULL, $driver_options=NULL) {
$this->PDO = new PDO($dsn, $user, $pass, $driver_options);
$this->numExecutes = 0;
$this->numStatements = 0;
}
public function __call($func, $args) {
return call_user_func_array(array(&$this->PDO, $func), $args);
}
public function prepare() {
$this->numStatements++;
$args = func_get_args();
$PDOS = call_user_func_array(array(&$this->PDO, 'prepare'), $args);
return new PDOpStatement($this, $PDOS);
}
public function query() {
$this->numExecutes++;
$this->numStatements++;
$args = func_get_args();
$PDOS = call_user_func_array(array(&$this->PDO, 'query'), $args);
return new PDOpStatement($this, $PDOS);
}
public function exec() {
$this->numExecutes++;
$args = func_get_args();
return call_user_func_array(array(&$this->PDO, 'exec'), $args);
}
}
class PDOpStatement implements IteratorAggregate {
protected $PDOS;
protected $PDOp;
public function __construct($PDOp, $PDOS) {
$this->PDOp = $PDOp;
$this->PDOS = $PDOS;
}
public function __call($func, $args) {
return call_user_func_array(array(&$this->PDOS, $func), $args);
}
public function bindColumn($column, &$param, $type=NULL) {
if ($type === NULL)
$this->PDOS->bindColumn($column, $param);
else
$this->PDOS->bindColumn($column, $param, $type);
}
public function bindParam($column, &$param, $type=NULL) {
if ($type === NULL)
$this->PDOS->bindParam($column, $param);
else
$this->PDOS->bindParam($column, $param, $type);
}
public function execute() {
$this->PDOp->numExecutes++;
$args = func_get_args();
return call_user_func_array(array(&$this->PDOS, 'execute'), $args);
}
public function __get($property) {
return $this->PDOS->$property;
}
public function getIterator() {
return $this->PDOS;
}
}
?>
Classes have properties with original PDO and PDOStatement objects, which are providing the functionality to PDOp and PDOpStatement.
From outside, PDOp and PDOpStatement look like PDO and PDOStatement, but also are providing wanted info.
Please note this:
Won't work:
$sth = $dbh->prepare('SELECT name, colour, calories FROM ? WHERE calories < ?');
THIS WORKS!
$sth = $dbh->prepare('SELECT name, colour, calories FROM fruit WHERE calories < ?');
The parameter cannot be applied on table names!!
When using prepared statements there is no official PDO feature to show you the final query string that is submitted to a database complete with the parameters you passed.
Use this simple function for debugging. The values you are passing may not be what you expect.
<?php
//Sample query string
$query = "UPDATE users SET name = :user_name WHERE id = :user_id";
//Sample parameters
$params = [':user_name' => 'foobear', ':user_id' => 1001];
function build_pdo_query($string, $array) {
//Get the key lengths for each of the array elements.
$keys = array_map('strlen', array_keys($array));
//Sort the array by string length so the longest strings are replaced first.
array_multisort($keys, SORT_DESC, $array);
foreach($array as $k => $v) {
//Quote non-numeric values.
$replacement = is_numeric($v) ? $v : "'{$v}'";
//Replace the needle.
$string = str_replace($k, $replacement, $string);
}
return $string;
}
echo build_pdo_query($query, $params); //UPDATE users SET name = 'foobear' WHERE id = 1001
?>
This is a little late... but I'm old and slow.......
Regarding Extending PDOStatement and PDO I found that sending the PDOExtended class by reference helps:
In the constructor after parent::__construct() :
$this->setAttribute(\PDO::ATTR_STATEMENT_CLASS,array('PDOStatementExtended', [&$this]));}
And in
class PDOStatementExtended extends \PDOStatement
{
protected function __construct
(
\PDO &$PDO,
)