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<?php
/* vim: set expandtab tabstop=4 shiftwidth=4 softtabstop=4: */
/**
* Provides an object interface to a table row
*
* PHP versions 4 and 5
*
* LICENSE: This source file is subject to version 3.0 of the PHP license
* that is available through the world-wide-web at the following URI:
* http://www.php.net/license/3_0.txt. If you did not receive a copy of
* the PHP License and are unable to obtain it through the web, please
* send a note to license@php.net so we can mail you a copy immediately.
*
* @category Database
* @package DB
* @author Stig Bakken <stig@php.net>
* @copyright 1997-2007 The PHP Group
* @license http://www.php.net/license/3_0.txt PHP License 3.0
* @version CVS: $Id$
* @link http://pear.php.net/package/DB
*/
/**
* Obtain the DB class so it can be extended from
*/
require_once 'DB.php';
/**
* Provides an object interface to a table row
*
* It lets you add, delete and change rows using objects rather than SQL
* statements.
*
* @category Database
* @package DB
* @author Stig Bakken <stig@php.net>
* @copyright 1997-2007 The PHP Group
* @license http://www.php.net/license/3_0.txt PHP License 3.0
* @version Release: @package_version@
* @link http://pear.php.net/package/DB
*/
class DB_storage extends PEAR
{
// {{{ properties
/** the name of the table (or view, if the backend database supports
updates in views) we hold data from */
var $_table = null;
/** which column(s) in the table contains primary keys, can be a
string for single-column primary keys, or an array of strings
for multiple-column primary keys */
var $_keycolumn = null;
/** DB connection handle used for all transactions */
var $_dbh = null;
/** an assoc with the names of database fields stored as properties
in this object */
var $_properties = array();
/** an assoc with the names of the properties in this object that
have been changed since they were fetched from the database */
var $_changes = array();
/** flag that decides if data in this object can be changed.
objects that don't have their table's key column in their
property lists will be flagged as read-only. */
var $_readonly = false;
/** function or method that implements a validator for fields that
are set, this validator function returns true if the field is
valid, false if not */
var $_validator = null;
// }}}
// {{{ constructor
/**
* Constructor
*
* @param $table string the name of the database table
*
* @param $keycolumn mixed string with name of key column, or array of
* strings if the table has a primary key of more than one column
*
* @param $dbh object database connection object
*
* @param $validator mixed function or method used to validate
* each new value, called with three parameters: the name of the
* field/column that is changing, a reference to the new value and
* a reference to this object
*
*/
function DB_storage($table, $keycolumn, &$dbh, $validator = null)
{
$this->PEAR('DB_Error');
$this->_table = $table;
$this->_keycolumn = $keycolumn;
$this->_dbh = $dbh;
$this->_readonly = false;
$this->_validator = $validator;
}
// }}}
// {{{ _makeWhere()
/**
* Utility method to build a "WHERE" clause to locate ourselves in
* the table.
*
* XXX future improvement: use rowids?
*
* @access private
*/
function _makeWhere($keyval = null)
{
if (is_array($this->_keycolumn)) {
if ($keyval === null) {
for ($i = 0; $i < sizeof($this->_keycolumn); $i++) {
$keyval[] = $this->{$this->_keycolumn[$i]};
}
}
$whereclause = '';
for ($i = 0; $i < sizeof($this->_keycolumn); $i++) {
if ($i > 0) {
$whereclause .= ' AND ';
}
$whereclause .= $this->_keycolumn[$i];
if (is_null($keyval[$i])) {
// there's not much point in having a NULL key,
// but we support it anyway
$whereclause .= ' IS NULL';
} else {
$whereclause .= ' = ' . $this->_dbh->quote($keyval[$i]);
}
}
} else {
if ($keyval === null) {
$keyval = @$this->{$this->_keycolumn};
}
$whereclause = $this->_keycolumn;
if (is_null($keyval)) {
// there's not much point in having a NULL key,
// but we support it anyway
$whereclause .= ' IS NULL';
} else {
$whereclause .= ' = ' . $this->_dbh->quote($keyval);
}
}
return $whereclause;
}
// }}}
// {{{ setup()
/**
* Method used to initialize a DB_storage object from the
* configured table.
*
* @param $keyval mixed the key[s] of the row to fetch (string or array)
*
* @return int DB_OK on success, a DB error if not
*/
function setup($keyval)
{
$whereclause = $this->_makeWhere($keyval);
$query = 'SELECT * FROM ' . $this->_table . ' WHERE ' . $whereclause;
$sth = $this->_dbh->query($query);
if (DB::isError($sth)) {
return $sth;
}
$row = $sth->fetchRow(DB_FETCHMODE_ASSOC);
if (DB::isError($row)) {
return $row;
}
if (!$row) {
return $this->raiseError(null, DB_ERROR_NOT_FOUND, null, null,
$query, null, true);
}
foreach ($row as $key => $value) {
$this->_properties[$key] = true;
$this->$key = $value;
}
return DB_OK;
}
// }}}
// {{{ insert()
/**
* Create a new (empty) row in the configured table for this
* object.
*/
function insert($newpk)
{
if (is_array($this->_keycolumn)) {
$primarykey = $this->_keycolumn;
} else {
$primarykey = array($this->_keycolumn);
}
settype($newpk, "array");
for ($i = 0; $i < sizeof($primarykey); $i++) {
$pkvals[] = $this->_dbh->quote($newpk[$i]);
}
$sth = $this->_dbh->query("INSERT INTO $this->_table (" .
implode(",", $primarykey) . ") VALUES(" .
implode(",", $pkvals) . ")");
if (DB::isError($sth)) {
return $sth;
}
if (sizeof($newpk) == 1) {
$newpk = $newpk[0];
}
$this->setup($newpk);
}
// }}}
// {{{ toString()
/**
* Output a simple description of this DB_storage object.
* @return string object description
*/
function toString()
{
$info = strtolower(get_class($this));
$info .= " (table=";
$info .= $this->_table;
$info .= ", keycolumn=";
if (is_array($this->_keycolumn)) {
$info .= "(" . implode(",", $this->_keycolumn) . ")";
} else {
$info .= $this->_keycolumn;
}
$info .= ", dbh=";
if (is_object($this->_dbh)) {
$info .= $this->_dbh->toString();
} else {
$info .= "null";
}
$info .= ")";
if (sizeof($this->_properties)) {
$info .= " [loaded, key=";
$keyname = $this->_keycolumn;
if (is_array($keyname)) {
$info .= "(";
for ($i = 0; $i < sizeof($keyname); $i++) {
if ($i > 0) {
$info .= ",";
}
$info .= $this->$keyname[$i];
}
$info .= ")";
} else {
$info .= $this->$keyname;
}
$info .= "]";
}
if (sizeof($this->_changes)) {
$info .= " [modified]";
}
return $info;
}
// }}}
// {{{ dump()
/**
* Dump the contents of this object to "standard output".
*/
function dump()
{
foreach ($this->_properties as $prop => $foo) {
print "$prop = ";
print htmlentities($this->$prop);
print "<br />\n";
}
}
// }}}
// {{{ &create()
/**
* Static method used to create new DB storage objects.
* @param $data assoc. array where the keys are the names
* of properties/columns
* @return object a new instance of DB_storage or a subclass of it
*/
function &create($table, &$data)
{
$classname = strtolower(get_class($this));
$obj = new $classname($table);
foreach ($data as $name => $value) {
$obj->_properties[$name] = true;
$obj->$name = &$value;
}
return $obj;
}
// }}}
// {{{ loadFromQuery()
/**
* Loads data into this object from the given query. If this
* object already contains table data, changes will be saved and
* the object re-initialized first.
*
* @param $query SQL query
*
* @param $params parameter list in case you want to use
* prepare/execute mode
*
* @return int DB_OK on success, DB_WARNING_READ_ONLY if the
* returned object is read-only (because the object's specified
* key column was not found among the columns returned by $query),
* or another DB error code in case of errors.
*/
// XXX commented out for now
/*
function loadFromQuery($query, $params = null)
{
if (sizeof($this->_properties)) {
if (sizeof($this->_changes)) {
$this->store();
$this->_changes = array();
}
$this->_properties = array();
}
$rowdata = $this->_dbh->getRow($query, DB_FETCHMODE_ASSOC, $params);
if (DB::isError($rowdata)) {
return $rowdata;
}
reset($rowdata);
$found_keycolumn = false;
while (list($key, $value) = each($rowdata)) {
if ($key == $this->_keycolumn) {
$found_keycolumn = true;
}
$this->_properties[$key] = true;
$this->$key = &$value;
unset($value); // have to unset, or all properties will
// refer to the same value
}
if (!$found_keycolumn) {
$this->_readonly = true;
return DB_WARNING_READ_ONLY;
}
return DB_OK;
}
*/
// }}}
// {{{ set()
/**
* Modify an attriute value.
*/
function set($property, $newvalue)
{
// only change if $property is known and object is not
// read-only
if ($this->_readonly) {
return $this->raiseError(null, DB_WARNING_READ_ONLY, null,
null, null, null, true);
}
if (@isset($this->_properties[$property])) {
if (empty($this->_validator)) {
$valid = true;
} else {
$valid = @call_user_func($this->_validator,
$this->_table,
$property,
$newvalue,
$this->$property,
$this);
}
if ($valid) {
$this->$property = $newvalue;
if (empty($this->_changes[$property])) {
$this->_changes[$property] = 0;
} else {
$this->_changes[$property]++;
}
} else {
return $this->raiseError(null, DB_ERROR_INVALID, null,
null, "invalid field: $property",
null, true);
}
return true;
}
return $this->raiseError(null, DB_ERROR_NOSUCHFIELD, null,
null, "unknown field: $property",
null, true);
}
// }}}
// {{{ &get()
/**
* Fetch an attribute value.
*
* @param string attribute name
*
* @return attribute contents, or null if the attribute name is
* unknown
*/
function &get($property)
{
// only return if $property is known
if (isset($this->_properties[$property])) {
return $this->$property;
}
$tmp = null;
return $tmp;
}
// }}}
// {{{ _DB_storage()
/**
* Destructor, calls DB_storage::store() if there are changes
* that are to be kept.
*/
function _DB_storage()
{
if (sizeof($this->_changes)) {
$this->store();
}
$this->_properties = array();
$this->_changes = array();
$this->_table = null;
}
// }}}
// {{{ store()
/**
* Stores changes to this object in the database.
*
* @return DB_OK or a DB error
*/
function store()
{
$params = array();
$vars = array();
foreach ($this->_changes as $name => $foo) {
$params[] = &$this->$name;
$vars[] = $name . ' = ?';
}
if ($vars) {
$query = 'UPDATE ' . $this->_table . ' SET ' .
implode(', ', $vars) . ' WHERE ' .
$this->_makeWhere();
$stmt = $this->_dbh->prepare($query);
$res = $this->_dbh->execute($stmt, $params);
if (DB::isError($res)) {
return $res;
}
$this->_changes = array();
}
return DB_OK;
}
// }}}
// {{{ remove()
/**
* Remove the row represented by this object from the database.
*
* @return mixed DB_OK or a DB error
*/
function remove()
{
if ($this->_readonly) {
return $this->raiseError(null, DB_WARNING_READ_ONLY, null,
null, null, null, true);
}
$query = 'DELETE FROM ' . $this->_table .' WHERE '.
$this->_makeWhere();
$res = $this->_dbh->query($query);
if (DB::isError($res)) {
return $res;
}
foreach ($this->_properties as $prop => $foo) {
unset($this->$prop);
}
$this->_properties = array();
$this->_changes = array();
return DB_OK;
}
// }}}
}
/*
* Local variables:
* tab-width: 4
* c-basic-offset: 4
* End:
*/
?>
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