Base dao class illustrating the usefulness of closures.
* Handles opening and closing of connections.
* Adds slashes sql
* Type checking of sql parameters and casts as appropriate
* Provides hook for processing of result set and emitting one or more objects.
* Provides hook for accessing underlying link and result objects.
<?php
define("userName","root");
define("password","root");
define("dbName","ahcdb");
define("hostName","localhost");
class BaseDao {
function getConnection() {
$link = mysql_connect(hostName, userName, password);
if (!$link)
die("Could not connect: " . mysql_error());
if (!mysql_select_db(dbName))
die("Could not select database: " . mysql_error());
return $link;
}
function setParams(& $sql, $params) {
if($params != null)
$sql = vsprintf($sql, array_map(function($n) {
if(is_int($n))
return (int)$n;
if(is_float($n))
return (float)$n;
if(is_string($n))
return "'".mysql_real_escape_string($n)."'";
return mysql_real_escape_string($n);
}, $params));
}
function executeQuery($sql, $params, $callback = null) {
$link = $this->getConnection();
$this->setParams($sql, $params);
$return = null;
if(($result = mysql_query($sql, $link)) != null)
if($callback != null)
$return = $callback($result, $link);
if($link != null)
mysql_close($link);
if(!$result)
die("Fatal Error: Invalid query '$sql' : " . mysql_error());
return $return;
}
function getList($sql, $params, $callback) {
return $this->executeQuery($sql, $params, function($result, $link) use ($callback) {
$idx = 0;
$list = array();
while ($row = mysql_fetch_assoc($result))
if($callback != null)
$list[$idx] = $callback($idx++, $row);
return $list;
});
}
function getSingle($sql, $params, $callback) {
return $this->executeQuery($sql, $params, function($result, $link) use ($callback) {
if ($row = mysql_fetch_assoc($result))
$obj = $callback($row);
return $obj;
});
}
}
class Example {
var $id;
var $name;
function Example($id, $name){
$this->id = $id;
$this->name = $name;
}
function setId($id){
$this->id = $id;
}
}
class ExampleDao extends BaseDao {
function getAll(){
return parent::getList("select * from nodes", null, function($idx, $row) {
return new Example($row["id"], $row["name"]);
});
}
function load($id){
return parent::getSingle("select * from nodes where id = %1\$s", array($id), function($row) {
return new Example($row["id"], $row["name"]);
});
}
function update($example){
return parent::executeQuery("update nodes set name = '' where id = -1", null, function($result, $link){
return $result;
});
}
function insert(& $example){
return parent::executeQuery("insert into nodes", null, function($result, $link) use ($example){
$id = mysql_insert_id($link);
$example->setId($id);
return $result;
});
}
}
$exampleDao = new ExampleDao();
$list = $exampleDao->getAll());
$exampleObject = $exampleDao->load(1));
$exampleDao->update($exampleObject);
?>