khanat-opennel-code/code/web/private_php/ams/autoload/dblayer.php

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2014-09-03 05:06:43 +00:00
<?php
/**
* Handles the database connections. It uses PDO to connect to the different databases. It will use the argument of the constructor to setup a connection to the database
* with the matching entry in the $cfg global variable.
*
* --> First create an object of dblayer --> $db = new DBLayer('short database name used in config')
*
* --> Insert --> $db->insert( $tb_name, $data )
* $tb_name = table name in which we want to insert data
* $data = array of data that needs to be inserted in format('fieldname' => $value) where fieldname must be a field in that table.
*
* --> select --> $db->select( $tb_name, $data, $where )
* $tb_name = table name which we want to select
* $data = array of data which is then required in WHERE clause in format array('fieldname'=>$value) fieldname must be a field in that table.
* $where = string in format ('fieldname=:fieldname') where :fieldname takes it's value from $data array.
*
* --> update --> $db->update( $tb_name, $data, $where )
* $tb_name = table name which we want to update
* $data = array of data which contains the filelds that need to be updated with their values in the format('fieldname' => $value,...) where fieldname must be a field in that table.
* $where = string contains the filename with a value at that field in the format ('fieldname = $value') where fieldname must be a field in that table and $value is value respect to that field.
*
* --> delete --> $db->delete( $tb_name, $data, $where )
* $tb_name = table name where we want to delete.
* $data = array of data which is then required in WHERE clause in format array('fieldname'=> $value) where fieldname must be a field in that table.
* $where = string in format ('fieldname=:fieldname') where :fieldname takes it's value from $data array.
*
*
* @author Daan Janssens, mentored by Matthew Lagoe
*
*/
// $PDOCache = array();
class DBLayer {
private $PDO;
// private $host;
// private $dbname;
/**
* The PDO object, instantiated by the constructor
*/
/**
* The constructor.
* Instantiates the PDO object attribute by connecting to the arguments matching database(the db info is stored in the $cfg global var)
*
* @param $db String, the name of the databases entry in the $cfg global var.
* @param $dbn String, the name of the databases entry in the $cfg global var if $db referenced to an action(install etc).
*/
function __construct($db, $dbn = null)
{
global $cfg;
// $this->host = $cfg['db'][$db]['host'];
// $this->dbname = $cfg['db'][$db]['name'];
/*global $PDOCache;
if (isset($PDOCache[$this->host])) {
$this->PDO = $PDOCache[$this->host]['pdo'];
} else {*/
$dsn = "mysql:";
$dsn .= "host=" . $cfg['db'][$db]['host'] . ";";
$dsn .= "dbname=" . $cfg['db'][$db]['name'] . ";"; // Comment this out when using the cache
$dsn .= "port=" . $cfg['db'][$db]['port'] . ";";
$opt = array(
PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION,
PDO::ATTR_DEFAULT_FETCH_MODE => PDO::FETCH_ASSOC,
PDO::ATTR_PERSISTENT => true
);
$this->PDO = new PDO($dsn, $cfg['db'][$db]['user'], $cfg['db'][$db]['pass'], $opt);
/* $PDOCache[$this->host] = array();
$PDOCache[$this->host]['pdo'] = $this->PDO;
$PDOCache[$this->host]['use'] = $this->dbname;
*/ //$this->PDO->query('USE ' . $this->dbname . ';'); // FIXME safety
/*}*/
}
function __destruct() {
$this->PDO = NULL;
}
function useDb() {
/*global $PDOCache;
if ($PDOCache[$this->host]['use'] != $this->dbname) {
$PDOCache[$this->host]['use'] = $this->dbname;
$this->PDO->query('USE ' . $this->dbname . ';'); // FIXME safety
}*/
}
/**
* Execute a query that doesn't have any parameters.
*
* @param $query the mysql query.
* @return returns a PDOStatement object.
*/
public function executeWithoutParams($query) {
$this->useDb();
$statement = $this->PDO->prepare($query);
$statement->execute();
return $statement;
}
/**
* Execute a query that has parameters.
*
* @param $query the mysql query.
* @param $params the parameters that are being used by the query.
* @return returns a PDOStatement object.
*/
public function execute( $query, $params ) {
$this->useDb();
$statement = $this -> PDO -> prepare( $query );
$statement -> execute( $params );
return $statement;
}
/**
* Insert function which returns id of the inserting field.
*
* @param $tb_name table name where we want to insert data.
* @param $data the parameters that are being inserted into table.
* @return returns the id of the last inserted element.
*/
public function executeReturnId($tb_name, $data, $datafunc = array()) {
$this->useDb();
$field_options = implode(',', array_merge(array_keys($data), array_keys($datafunc)));
$field_values = implode(',', array_merge(array(':' . implode(',:', array_keys($data))), array_values($datafunc)));
try {
$sth = $this -> PDO -> prepare( "INSERT INTO $tb_name ($field_options) VALUE ($field_values)" );
foreach ($data as $key => $value) {
$sth->bindValue( ":$key", $value );
}
$sth->execute();
$lastId = $this->PDO->lastInsertId();
}
catch (Exception $e) {
throw $e; // new Exception( "error in inseting" );
}
return $lastId;
}
/**
* Select function using prepared statement.
* For selecting particular fields.
*
* @param string $param field to select, can be multiple fields.
* @param string $tb_name Table Name to Select.
* @param array $data array of data to be used in WHERE clause in format('fieldname'=>$value). 'fieldname' must be a field in that table.
* @param string $where where to select.
* @return statement object.
*/
public function selectWithParameter( $param, $tb_name, $data, $where ) {
$this->useDb();
try {
$sth = $this->PDO->prepare("SELECT $param FROM $tb_name WHERE $where");
$sth->execute($data);
}
catch (Exception $e) {
throw $e; // new Exception( "error selection" );
return false;
}
return $sth;
}
/**
* Select function using prepared statement.
* For selecting all fields in a table.
*
* @param string $tb_name Table Name to Select.
* @param array $data array of data to be used with WHERE part in format('fieldname'=>$value,...). 'fieldname' must be a field in that table.
* @param string $where where to select in format('fieldname=:fieldname' AND ...).
* @return statement object.
*/
public function select($tb_name, $data , $where) {
$this->useDb();
try {
$sth = $this->PDO->prepare("SELECT * FROM $tb_name WHERE $where");
$sth->execute( $data );
}
catch (Exception $e) {
throw $e; // new Exception( "error selection" );
return false;
}
return $sth;
}
/**
* Update function with prepared statement.
*
* @param string $tb_name name of the table on which operation to be performed.
* @param array $data array of data in format('fieldname' => $value,...).Here, only those fields must be stored which needs to be updated.
* @param string $where where part in format ('fieldname'= $value AND ...). 'fieldname' must be a field in that table.
* @throws Exception error in updating.
*/
public function update($tb_name, $data, $where) {
$this->useDb();
$field_option_values = null;
foreach ( $data as $key => $value ) {
$field_option_values .= ",$key" . '=:' . $key;
}
$field_option_values = ltrim($field_option_values, ',');
try {
$sth = $this->PDO->prepare("UPDATE $tb_name SET $field_option_values WHERE $where ");
foreach ($data as $key => $value) {
$sth->bindValue(":$key", $value);
}
$sth->execute();
}
catch (Exception $e) {
throw $e; // new Exception( 'error in updating' );
return false;
}
return true;
}
/**
* insert function using prepared statements.
*
* @param string $tb_name Name of the table on which operation to be performed.
* @param array $data array of data to insert in format('fieldname' => $value,....). 'fieldname' must be a field in that table.
* @throws error in inserting.
*/
public function insert($tb_name, $data, $datafunc = array()) {
$this->useDb();
$field_options = implode(',', array_merge(array_keys($data), array_keys($datafunc)));
$field_values = implode(',', array_merge(array(':' . implode(',:', array_keys($data))), array_values($datafunc)));
try {
$sth = $this->PDO->prepare("INSERT INTO $tb_name ($field_options) VALUE ($field_values)");
foreach ($data as $key => $value) {
$sth->bindValue(":$key", $value);
}
$sth->execute();
}
catch (Exception $e) {
throw $e; // new Exception("error in inserting");
}
}
/**
* Delete database entery using prepared statement.
*
* @param string $tb_name table name on which operations to be performed.
* @param $data array with values in the format('fieldname'=> $value,...). 'fieldname' must be a field in that table.
* @param string $where condition based on $data array in the format('fieldname=:fieldname' AND ...).
* @throws error in deleting.
*/
public function delete( $tb_name, $data, $where ) {
$this->useDb();
try {
$sth = $this->PDO->prepare("DELETE FROM $tb_name WHERE $where");
$sth->execute($data);
}
catch (Exception $e) {
throw $e; // new Exception( "error in deleting" );
}
}
}