<?php
function execute_sql($sql)
{
	$result = mysql_query($sql);
	if (!$result)
	{
		$error = mysql_errno() . ' - ' . mysql_error();
		echo $error;
		throw new Exception($error);
	}
	return $result;
}

function get_record($sql, $record_not_found_msg = 'Record not found.')
{
	$record = array();
	
	$result = execute_sql($sql);
	
	if ($row = mysql_fetch_assoc($result))
	{
		$record = $row;
		mysql_free_result($result);
	}
	else
	{
		echo $record_not_found_msg;
		throw new Exception($record_not_found_msg);
	}
	
	return $record;
}

function &get_records($sql)
{
	$result = execute_sql($sql);
	$records = array();
	while ($row = mysql_fetch_assoc($result))
		$records[] = $row;
	mysql_free_result($result);
	return $records;
}

function save($id, $table, array $save_values, &$action=NULL, array &$model=array())
{
	// get table columns
	$sql = "SELECT column_name FROM information_schema.columns WHERE table_schema = (SELECT DATABASE()) AND table_name = '$table'";
	$tmp_records = get_records($sql);
	$columns = array();
	foreach ($tmp_records as $tmp_record)
		$columns[] = '`' . $tmp_record['column_name'] . '`';
	
	// build save sql
	$values = array();
	foreach ($save_values as $key => $value)
	{
		$variable = $key;
		$column = '`' . $variable . '`';
		$$variable = $value;
		$html_variable = 'html_' . $variable;
		$$html_variable = htmlspecialchars($$variable, ENT_QUOTES);
		$mysql_variable = 'mysql_' . $variable;
		$$mysql_variable = empty($$variable) && strlen($$variable) == 0 ? 'NULL' : ("'" . mysql_real_escape_string($$html_variable) . "'");
		
		$model[$variable] = $$html_variable;
		
		if (in_array($column, $columns))
			$values[$column] = $$mysql_variable;
	}
	if (empty($id))
	{
		// create
		if (in_array('`create_on`', $columns))
			$values['`create_on`'] = 'NOW()';

		$sql = "INSERT INTO `$table` (" . implode(', ', array_keys($values)) . ") VALUES (" . implode(', ', array_values($values)) . ")";

		$action = 'Created';
	}
	else
	{
		// update
		$segments = array();
		foreach ($values as $column => $value)
			$segments[] = "$column = $value";
		$sql = "UPDATE `$table` SET " . implode(', ', $segments) . " WHERE id = $id";

		$action = 'Updated';
	}
	execute_sql($sql);
	if (empty($id))
		$id = mysql_insert_id();
	
	return $id;
}