table = &$table;
	$this->keyfieldname = $keyfieldname;
}
/**
 * Change active key field
 * @param $keyfieldname Optional name of primary key field, defaults to 'ID'
 */
function set_key_field($keyfieldname='ID')
{
	$this->keyfieldname = $keyfieldname;
	$this->key = isset($this->data[$keyfieldname]) ? $this->data[$keyfieldname] : '';
}
/**
 * Select a set of records of this table according to an array of selection
 * and sorting criteria.
 * Use fetch_next() to iterate through the result set
 * Example:
 * $record->select(array('Type' => 'bar', 'Date >=' => '1999-01-01',
 *    '-Date <' => 'NOW()', 'User NI' => 'chris'), 'ORDER BY Date');
 *
 * @param $params optional array of fieldname => value tupels.
 * These are ANDed to form a WHERE clause.
 * fieldname can contain an operator (separated by space), the
 * default operator is '='. The special operator 'NI' specifies
 * that the argument must be contained in a comma-separated list.
 *
 * @param $sql Optional SQL addendum added after $params (ORDER BY etc.)
 * @param $fields Optional field list to select (defaults to '*')
 * @return Number of rows that matched this query
 * @see it_db_record::fetch_next, it_db_table::construct_sql_clause
 *
 */
function select($params='', $sql='', $fields='*')
{
	$this->handle = $this->table->safe_sql_select($this->table->construct_sql_clause($params, $sql), $fields);
	return $this->table->db->num_rows($this->handle);
}
/**
 * Post-process data after reading a record.
 * This is a stub-function that can be overloaded.
 */
function _read_post_process()
{
}
/**
 * Pre-process data before writing a record.
 * This is a stub-function that can be overloaded.
 * @param $tags Reference to update/create tags, can be modified as needed
 */
function _write_pre_process(&$tags)
{
}
/**
 * Fetch the next record of a select() query
 * @return true if a record was successfully fetched, false otherwise
 * @see it_db_record::select
 */
function fetch_next()
{
	return $this->fetch($this->handle);
}
/**
 * Fetch the next record from an SQL result into this object.
 * If no more records are pending, clear the object's data.
 * @param $sqlresult Result of table::sql_select() or similar
 * @return 1 if a record was successfully fetched, 0 otherwise
 */
function fetch(&$sqlresult)
{
	$result = 0;
	if ($this->data = $this->table->db->fetch_assoc($sqlresult))
	{
		$this->key = $this->data[$this->keyfieldname];
		$result = 1;
	}
	else
	{
		$this->key = "";	/* "No record is loaded" */
		$this->data = array();	/* Clear local record data */
	}
	$this->_read_post_process();
	return  $result;
}
/**
 * Read a record from table
 * @param $key key field value of the desired row
 * @return 1 on success, 0 otherwise
 */
function read($key)
{
	$result = 0;
	if ($key != "")
	{
		$result = $this->fetch($this->table->safe_sql_select("WHERE $this->keyfieldname='" . mysql_real_escape_string($key) . "'"));
	}
	else
	{
		$this->key = "";	/* "No record is loaded" */
		$this->data = array();	/* Clear local record data */
	}
	$this->_read_post_process();
	return $result;
}
/**
 * Create a new record in the table
 * @see it_db_record::record_create, it_db_record::safe_create
 * @param $tags array of Fieldname/Value pairs
 * @param $replace use REPLACE (1) instead of INSERT (otherwise)
 * @return MySQL result (0 means failure)
 */
function create($tags, $replace=0)
{
	/* Pre-processing, $tags is passed by reference and may be modified here */
	$this->_write_pre_process($tags);
	$sql = $replace ? "REPLACE" : "INSERT";
	$sql .= " INTO " . $this->table->name . " (";
	$sql2 = '';
	unset($this->data);
	for ($sep=""; $ti = each($tags); $sep=",")
	{
		/* If the field name starts with '-', the value is taken as raw, no escaping
		   is done and no quotes are put around it. */
		if (substr($ti[0], 0, 1) == '-')
		{
			$ti[0] = substr($ti[0], 1);	/* Strip that '-' sign */
			$val = $ti[1];
		}
		else
			$val = isset($ti[1]) ? "'".mysql_real_escape_string($ti[1])."'" : 'NULL';
		$this->data[$ti[0]] = $ti[1];	/* Store data for later use */
		$sql .= $sep . $ti[0];
		$sql2 .= "$sep$val";
	}
	$sql .= ") VALUES ($sql2)";
	if ($result = $this->table->db->sql_query($sql))
	{
		/* If the key element was not given, it means it's an AUTO_INCREMENT thingy. */
		if (($this->key = $this->data[$this->keyfieldname]) == "")
		{
			$result = $this->table->db->safe_sql_query("SELECT LAST_INSERT_ID()");
			$this->key = mysql_result($result, 0, 0);
		}
		/* We need all fields from record, not only those we initialised */
		$this->read($this->key);
	}
	return $result;
}
/**
 * Safe version of create (doesn't return in case of failure)
 * @see it_db_record::create, it_db_record::record_create
 * @param $tags array of Fieldname/Value pairs
 * @param $replace use REPLACE (1) instead of INSERT (otherwise)
 * @return MySQL result (0 means failure)
 */
function safe_create($tags, $replace=0)
{
	if ($result = $this->create($tags, $replace))
		return $result;
	else
		fail("it_db_record::safe_create() failed: " . $this->table->db->error());
}
/**
 * Update a record in the table
 * @param $tags array of Fieldname/Value pairs
 * @return MySQL result (0 means failure)
 */
function update($tags)
{
	/* Pre-processing, $tags is passed by reference and may be modified here */
	$this->_write_pre_process($tags);
	if ($this->key == "")
		internal_error("it_db_record::update(): can't update undefined record");
	/* If we have nothing to do, return instead of performing an invalid SQL query */
	if (!count($tags))
		return true;
	$sql = "UPDATE " . $this->table->name . " SET ";
	for ($sep="", $raw=0; $ti = each($tags); $sep=",")
	{
		/* If the field name starts with '-', the value is taken as raw, no escaping
		   is done and no quotes are put around it. */
		if (substr($ti[0], 0, 1) == '-')
		{
			$ti[0] = substr($ti[0], 1);	/* Strip that '-' sign */
			$val = $ti[1];
			$raw++;
		}
		else
			$val = "'".mysql_real_escape_string($ti[1])."'";
		$sql .= $sep.$ti[0].'='.$val;
		if ($ti[0] == $this->key)
		{
			if ($this->data[$this->keyfieldname] != $ti[0])
				internal_error("$sql: trying to change key from $this->key.");
		}
		$this->data[$ti[0]] = $ti[1];
	}
	$sql .= " WHERE " . $this->keyfieldname . "='" . mysql_real_escape_string($this->key) . "'";
	/* debug("it_db_record::update(): $sql"); */
	$ret = $this->table->db->safe_sql_query($sql);
	/* Only re-read record if necessary (for performance), but always do post-processing. */
	if ($raw)
		$this->read($this->key);
	else
		$this->_read_post_process();
	return $ret;
}
/**
 * Delete the current record from the database
 * @param $key keyfield value of the record to be deleted. If this is missing, the current record is deleted. 
 * @return MySQL result (0 means failure)
 */
function delete($key="")
{
	if (!$key) $key = $this->key;
	if (($this->table->name == "") || ($this->keyfieldname == "") || ($key == ""))
		internal_error("it_db_record::delete(): no record\n");
	$sql = "DELETE FROM " . $this->table->name . " WHERE ". $this->keyfieldname . "='" . mysql_real_escape_string($key) . "'";
	if ($result = $this->table->db->sql_query($sql))
	{
		$this->key = "";
		$this->data = array();
	}
	return $result;
}
/**
 * Return a field of a record.
 * @param $field field name
 * @return field value. If the field does not exists, issue an
 * error message and terminate program execution.
 */
function safe_get_field($field)
{
	if ($field)
	{
		if (isset($this->data[$field]))
			return $this->data[$field];
		else internal_error("it_db_record::safe_get_field(): field \"$field\" not present in record.");
	}
	else internal_error("it_db_record::safe_get_field(): empty field name");
}
/**
 * Output all fields of a record in (ugly) html format
 */
function dump_html()
{
	echo "
Dump of table " . $this->table->name . ", record " . $this->keyfieldname . " = \"" . $this->key . "\":
\n";
	reset($this->data); next($this->data);
	while(list($key, $value) = each($this->data))
	{
		if ($key > 0) continue;	/* $$$ ugly */
		echo $key . " = \"" . htmlspecialchars($value) . "\"\n";
	}
	echo "