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<?php defined('SYSPATH') OR die('No direct access allowed.');
/**
* Provides database access in a platform agnostic way, using simple query building blocks.
*
* $Id: Database.php 4342 2009-05-08 16:56:01Z jheathco $
*
* @package Core
* @author Kohana Team
* @copyright (c) 2007-2008 Kohana Team
* @license http://kohanaphp.com/license.html
*/
class Database {

// Database instances
public static $instances = array();

// Global benchmark
public static $benchmarks = array();

// Configuration
protected $config = array
(
'benchmark' => FALSE,
'persistent' => FALSE,
'connection' => '',
'character_set' => 'utf8',
'table_prefix' => '',
'object' => TRUE,
'cache' => FALSE,
'escape' => TRUE,
);

// Database driver object
protected $driver;
protected $link;

// Un-compiled parts of the SQL query
protected $select = array();
protected $set = array();
protected $from = array();
protected $join = array();
protected $where = array();
protected $orderby = array();
protected $order = array();
protected $groupby = array();
protected $having = array();
protected $distinct = FALSE;
protected $limit = FALSE;
protected $offset = FALSE;
protected $last_query = '';

// Stack of queries for push/pop
protected $query_history = array();

/**
* Returns a singleton instance of Database.
*
* @param mixed configuration array or DSN
* @return Database
*/
public static function & instance($name = 'default', $config = NULL)
{
if ( ! isset(Database::$instances[$name]))
{
// Create a new instance
Database::$instances[$name] = new Database($config === NULL ? $name : $config);
}

return Database::$instances[$name];
}

/**
* Returns the name of a given database instance.
*
* @param Database instance of Database
* @return string
*/
public static function instance_name(Database $db)
{
return array_search($db, Database::$instances, TRUE);
}

/**
* Sets up the database configuration, loads the Database_Driver.
*
* @throws Kohana_Database_Exception
*/
public function __construct($config = array())
{
if (!is_array($config) && count($config))
{
// Parse the DSN, creating an array to hold the connection parameters
$db = array
(
'type' => 'mysql',
'user' => FALSE,
'pass' => FALSE,
'host' => FALSE,
'port' => FALSE,
'socket' => FALSE,
'database' => FALSE
);

// Reset the connection array to the database config
$this->config['connection'] = $db;

if (Config::get('db_type') != '')
$this->config['connection']['type'] = Config::get('db_type');

$this->config['connection']['user'] = Config::get('db_user');
$this->config['connection']['pass'] = Config::get('db_password');
$this->config['connection']['host'] = Config::get('db_host');
$this->config['connection']['database'] = Config::get('db_name');

$this->config['table_prefix'] = Config::get('db_table_prefix');
}
else
{
$this->config['connection'] = $config;
}

// Set driver name
$driver = 'Database_'.ucfirst($this->config['connection']['type']).'_Driver';

// Load the driver
if ( ! Kohana::auto_load($driver))
throw new Kohana_Database_Exception('core.driver_not_found', $this->config['connection']['type'], get_class($this));

// Initialize the driver
$this->driver = new $driver($this->config);

// Validate the driver
if ( ! ($this->driver instanceof Database_Driver))
throw new Kohana_Database_Exception('core.driver_implements', $this->config['connection']['type'], get_class($this), 'Database_Driver');

Log::add('debug', 'Database Library initialized');
}

/**
* Simple connect method to get the database queries up and running.
*
* @return void
*/
public function connect()
{
// A link can be a resource or an object
if ( ! is_resource($this->link) AND ! is_object($this->link))
{
$this->link = $this->driver->connect();
if ( ! is_resource($this->link) AND ! is_object($this->link))
throw new Kohana_Database_Exception('database.connection', $this->driver->show_error());

// Clear password after successful connect
$this->config['connection']['pass'] = NULL;
}
}

/**
* Runs a query into the driver and returns the result.
*
* @param string SQL query to execute
* @return Database_Result
*/
public function query($sql = '')
{
if ($sql == '') return FALSE;

// No link? Connect!
$this->link or $this->connect();

// Start the benchmark
$start = microtime(TRUE);

if (func_num_args() > 1) //if we have more than one argument ($sql)
{
$argv = func_get_args();
$binds = (is_array(next($argv))) ? current($argv) : array_slice($argv, 1);
}

// Compile binds if needed
if (isset($binds))
{
$sql = $this->compile_binds($sql, $binds);
}

// Fetch the result
$result = $this->driver->query($this->last_query = $sql);

// Stop the benchmark
$stop = microtime(TRUE);

if ($this->config['benchmark'] == TRUE)
{
// Benchmark the query
Database::$benchmarks[] = array('query' => $sql, 'time' => $stop - $start, 'rows' => count($result));
}

return $result;
}

/**
* Selects the column names for a database query.
*
* @param string string or array of column names to select
* @return Database This Database object.
*/
public function select($sql = '*')
{
if (func_num_args() > 1)
{
$sql = func_get_args();
}
elseif (is_string($sql))
{
$sql = explode(',', $sql);
}
else
{
$sql = (array) $sql;
}

foreach ($sql as $val)
{
if (($val = trim($val)) === '') continue;

if (strpos($val, '(') === FALSE AND $val !== '*')
{
if (preg_match('/^DISTINCT\s++(.+)$/i', $val, $matches))
{
// Only prepend with table prefix if table name is specified
$val = (strpos($matches[1], '.') !== FALSE) ? $this->config['table_prefix'].$matches[1] : $matches[1];

$this->distinct = TRUE;
}
else
{
$val = (strpos($val, '.') !== FALSE) ? $this->config['table_prefix'].$val : $val;
}

$val = $this->driver->escape_column($val);
}

$this->select[] = $val;
}

return $this;
}

/**
* Selects the from table(s) for a database query.
*
* @param string string or array of tables to select
* @return Database This Database object.
*/
public function from($sql)
{
if (func_num_args() > 1)
{
$sql = func_get_args();
}
elseif (is_string($sql))
{
$sql = explode(',', $sql);
}
else
{
$sql = array($sql);
}

foreach ($sql as $val)
{
if (is_string($val))
{
if (($val = trim($val)) === '') continue;

// TODO: Temporary solution, this should be moved to database driver (AS is checked for twice)
if (stripos($val, ' AS ') !== FALSE)
{
$val = str_ireplace(' AS ', ' AS ', $val);

list($table, $alias) = explode(' AS ', $val);

// Attach prefix to both sides of the AS
$val = $this->config['table_prefix'].$table.' AS '.$this->config['table_prefix'].$alias;
}
else
{
$val = $this->config['table_prefix'].$val;
}
}

$this->from[] = $val;
}

return $this;
}

/**
* Generates the JOIN portion of the query.
*
* @param string table name
* @param string|array where key or array of key => value pairs
* @param string where value
* @param string type of join
* @return Database This Database object.
*/
public function join($table, $key, $value = NULL, $type = '')
{
$join = array();

if ( ! empty($type))
{
$type = strtoupper(trim($type));

if ( ! in_array($type, array('LEFT', 'RIGHT', 'OUTER', 'INNER', 'LEFT OUTER', 'RIGHT OUTER'), TRUE))
{
$type = '';
}
else
{
$type .= ' ';
}
}

$cond = array();
$keys = is_array($key) ? $key : array($key => $value);
foreach ($keys as $key => $value)
{
$key = (strpos($key, '.') !== FALSE) ? $this->config['table_prefix'].$key : $key;

if (is_string($value))
{
// Only escape if it's a string
$value = $this->driver->escape_column($this->config['table_prefix'].$value);
}

$cond[] = $this->driver->where($key, $value, 'AND ', count($cond), FALSE);
}

if ( ! is_array($this->join))
{
$this->join = array();
}

if ( ! is_array($table))
{
$table = array($table);
}

foreach ($table as $t)
{
if (is_string($t))
{
// TODO: Temporary solution, this should be moved to database driver (AS is checked for twice)
if (stripos($t, ' AS ') !== FALSE)
{
$t = str_ireplace(' AS ', ' AS ', $t);

list($table, $alias) = explode(' AS ', $t);

// Attach prefix to both sides of the AS
$t = $this->config['table_prefix'].$table.' AS '.$this->config['table_prefix'].$alias;
}
else
{
$t = $this->config['table_prefix'].$t;
}
}

$join['tables'][] = $this->driver->escape_column($t);
}

$join['conditions'] = '('.trim(implode(' ', $cond)).')';
$join['type'] = $type;

$this->join[] = $join;

return $this;
}


/**
* Selects the where(s) for a database query.
*
* @param string|array key name or array of key => value pairs
* @param string value to match with key
* @param boolean disable quoting of WHERE clause
* @return Database This Database object.
*/
public function where($key, $value = NULL, $quote = TRUE)
{
$quote = (func_num_args() < 2 AND ! is_array($key)) ? -1 : $quote;
if (is_object($key))
{
$keys = array((string) $key => '');
}
elseif ( ! is_array($key))
{
$keys = array($key => $value);
}
else
{
$keys = $key;
}

foreach ($keys as $key => $value)
{
$key = (strpos($key, '.') !== FALSE) ? $this->config['table_prefix'].$key : $key;
$this->where[] = $this->driver->where($key, $value, 'AND ', count($this->where), $quote);
}

return $this;
}

/**
* Selects the or where(s) for a database query.
*
* @param string|array key name or array of key => value pairs
* @param string value to match with key
* @param boolean disable quoting of WHERE clause
* @return Database This Database object.
*/
public function orwhere($key, $value = NULL, $quote = TRUE)
{
$quote = (func_num_args() < 2 AND ! is_array($key)) ? -1 : $quote;
if (is_object($key))
{
$keys = array((string) $key => '');
}
elseif ( ! is_array($key))
{
$keys = array($key => $value);
}
else
{
$keys = $key;
}

foreach ($keys as $key => $value)
{
$key = (strpos($key, '.') !== FALSE) ? $this->config['table_prefix'].$key : $key;
$this->where[] = $this->driver->where($key, $value, 'OR ', count($this->where), $quote);
}

return $this;
}

/**
* Selects the like(s) for a database query.
*
* @param string|array field name or array of field => match pairs
* @param string like value to match with field
* @param boolean automatically add starting and ending wildcards
* @return Database This Database object.
*/
public function like($field, $match = '', $auto = TRUE)
{
$fields = is_array($field) ? $field : array($field => $match);

foreach ($fields as $field => $match)
{
$field = (strpos($field, '.') !== FALSE) ? $this->config['table_prefix'].$field : $field;
$this->where[] = $this->driver->like($field, $match, $auto, 'AND ', count($this->where));
}

return $this;
}

/**
* Selects the or like(s) for a database query.
*
* @param string|array field name or array of field => match pairs
* @param string like value to match with field
* @param boolean automatically add starting and ending wildcards
* @return Database This Database object.
*/
public function orlike($field, $match = '', $auto = TRUE)
{
$fields = is_array($field) ? $field : array($field => $match);

foreach ($fields as $field => $match)
{
$field = (strpos($field, '.') !== FALSE) ? $this->config['table_prefix'].$field : $field;
$this->where[] = $this->driver->like($field, $match, $auto, 'OR ', count($this->where));
}

return $this;
}

/**
* Selects the not like(s) for a database query.
*
* @param string|array field name or array of field => match pairs
* @param string like value to match with field
* @param boolean automatically add starting and ending wildcards
* @return Database This Database object.
*/
public function notlike($field, $match = '', $auto = TRUE)
{
$fields = is_array($field) ? $field : array($field => $match);

foreach ($fields as $field => $match)
{
$field = (strpos($field, '.') !== FALSE) ? $this->config['table_prefix'].$field : $field;
$this->where[] = $this->driver->notlike($field, $match, $auto, 'AND ', count($this->where));
}

return $this;
}

/**
* Selects the or not like(s) for a database query.
*
* @param string|array field name or array of field => match pairs
* @param string like value to match with field
* @return Database This Database object.
*/
public function ornotlike($field, $match = '', $auto = TRUE)
{
$fields = is_array($field) ? $field : array($field => $match);

foreach ($fields as $field => $match)
{
$field = (strpos($field, '.') !== FALSE) ? $this->config['table_prefix'].$field : $field;
$this->where[] = $this->driver->notlike($field, $match, $auto, 'OR ', count($this->where));
}

return $this;
}

/**
* Selects the like(s) for a database query.
*
* @param string|array field name or array of field => match pairs
* @param string like value to match with field
* @return Database This Database object.
*/
public function regex($field, $match = '')
{
$fields = is_array($field) ? $field : array($field => $match);

foreach ($fields as $field => $match)
{
$field = (strpos($field, '.') !== FALSE) ? $this->config['table_prefix'].$field : $field;
$this->where[] = $this->driver->regex($field, $match, 'AND ', count($this->where));
}

return $this;
}

/**
* Selects the or like(s) for a database query.
*
* @param string|array field name or array of field => match pairs
* @param string like value to match with field
* @return Database This Database object.
*/
public function orregex($field, $match = '')
{
$fields = is_array($field) ? $field : array($field => $match);

foreach ($fields as $field => $match)
{
$field = (strpos($field, '.') !== FALSE) ? $this->config['table_prefix'].$field : $field;
$this->where[] = $this->driver->regex($field, $match, 'OR ', count($this->where));
}

return $this;
}

/**
* Selects the not regex(s) for a database query.
*
* @param string|array field name or array of field => match pairs
* @param string regex value to match with field
* @return Database This Database object.
*/
public function notregex($field, $match = '')
{
$fields = is_array($field) ? $field : array($field => $match);

foreach ($fields as $field => $match)
{
$field = (strpos($field, '.') !== FALSE) ? $this->config['table_prefix'].$field : $field;
$this->where[] = $this->driver->notregex($field, $match, 'AND ', count($this->where));
}

return $this;
}

/**
* Selects the or not regex(s) for a database query.
*
* @param string|array field name or array of field => match pairs
* @param string regex value to match with field
* @return Database This Database object.
*/
public function ornotregex($field, $match = '')
{
$fields = is_array($field) ? $field : array($field => $match);

foreach ($fields as $field => $match)
{
$field = (strpos($field, '.') !== FALSE) ? $this->config['table_prefix'].$field : $field;
$this->where[] = $this->driver->notregex($field, $match, 'OR ', count($this->where));
}

return $this;
}

/**
* Chooses the column to group by in a select query.
*
* @param string column name to group by
* @return Database This Database object.
*/
public function groupby($by)
{
if ( ! is_array($by))
{
$by = explode(',', (string) $by);
}

foreach ($by as $val)
{
$val = trim($val);

if ($val != '')
{
// Add the table prefix if we are using table.column names
if(strpos($val, '.'))
{
$val = $this->config['table_prefix'].$val;
}

$this->groupby[] = $this->driver->escape_column($val);
}
}

return $this;
}

/**
* Selects the having(s) for a database query.
*
* @param string|array key name or array of key => value pairs
* @param string value to match with key
* @param boolean disable quoting of WHERE clause
* @return Database This Database object.
*/
public function having($key, $value = '', $quote = TRUE)
{
$this->having[] = $this->driver->where($key, $value, 'AND', count($this->having), TRUE);
return $this;
}

/**
* Selects the or having(s) for a database query.
*
* @param string|array key name or array of key => value pairs
* @param string value to match with key
* @param boolean disable quoting of WHERE clause
* @return Database This Database object.
*/
public function orhaving($key, $value = '', $quote = TRUE)
{
$this->having[] = $this->driver->where($key, $value, 'OR', count($this->having), TRUE);
return $this;
}

/**
* Chooses which column(s) to order the select query by.
*
* @param string|array column(s) to order on, can be an array, single column, or comma seperated list of columns
* @param string direction of the order
* @return Database This Database object.
*/
public function orderby($orderby, $direction = NULL)
{
if ( ! is_array($orderby))
{
$orderby = array($orderby => $direction);
}

foreach ($orderby as $column => $direction)
{
$direction = strtoupper(trim($direction));

// Add a direction if the provided one isn't valid
if ( ! in_array($direction, array('ASC', 'DESC', 'RAND()', 'RANDOM()', 'NULL')))
{
$direction = 'ASC';
}

// Add the table prefix if a table.column was passed
if (strpos($column, '.'))
{
$column = $this->config['table_prefix'].$column;
}

$this->orderby[] = $this->driver->escape_column($column).' '.$direction;
}

return $this;
}

/**
* Selects the limit section of a query.
*
* @param integer number of rows to limit result to
* @param integer offset in result to start returning rows from
* @return Database This Database object.
*/
public function limit($limit, $offset = NULL)
{
$this->limit = (int) $limit;

if ($offset !== NULL OR ! is_int($this->offset))
{
$this->offset($offset);
}

return $this;
}

/**
* Sets the offset portion of a query.
*
* @param integer offset value
* @return Database This Database object.
*/
public function offset($value)
{
$this->offset = (int) $value;

return $this;
}

/**
* Allows key/value pairs to be set for inserting or updating.
*
* @param string|array key name or array of key => value pairs
* @param string value to match with key
* @return Database This Database object.
*/
public function set($key, $value = '')
{
if ( ! is_array($key))
{
$key = array($key => $value);
}

foreach ($key as $k => $v)
{
// Add a table prefix if the column includes the table.
if (strpos($k, '.'))
$k = $this->config['table_prefix'].$k;

$this->set[$k] = $this->driver->escape($v);
}

return $this;
}

/**
* Compiles the select statement based on the other functions called and runs the query.
*
* @param string table name
* @param string limit clause
* @param string offset clause
* @return Database_Result
*/
public function get($table = '', $limit = NULL, $offset = NULL)
{
if ($table != '')
{
$this->from($table);
}

if ( ! is_null($limit))
{
$this->limit($limit, $offset);
}

$sql = $this->driver->compile_select(get_object_vars($this));

$this->reset_select();

$result = $this->query($sql);

$this->last_query = $sql;

return $result;
}

/**
* Compiles the select statement based on the other functions called and runs the query.
*
* @param string table name
* @param array where clause
* @param string limit clause
* @param string offset clause
* @return Database This Database object.
*/
public function getwhere($table = '', $where = NULL, $limit = NULL, $offset = NULL)
{
if ($table != '')
{
$this->from($table);
}

if ( ! is_null($where))
{
$this->where($where);
}

if ( ! is_null($limit))
{
$this->limit($limit, $offset);
}

$sql = $this->driver->compile_select(get_object_vars($this));

$this->reset_select();

$result = $this->query($sql);

return $result;
}

/**
* Compiles the select statement based on the other functions called and returns the query string.
*
* @param string table name
* @param string limit clause
* @param string offset clause
* @return string sql string
*/
public function compile($table = '', $limit = NULL, $offset = NULL)
{
if ($table != '')
{
$this->from($table);
}

if ( ! is_null($limit))
{
$this->limit($limit, $offset);
}

$sql = $this->driver->compile_select(get_object_vars($this));

$this->reset_select();

return $sql;
}

/**
* Compiles an insert string and runs the query.
*
* @param string table name
* @param array array of key/value pairs to insert
* @return Database_Result Query result
*/
public function insert($table = '', $set = NULL)
{
if ( ! is_null($set))
{
$this->set($set);
}

if ($this->set == NULL)
throw new Kohana_Database_Exception('database.must_use_set');

if ($table == '')
{
if ( ! isset($this->from[0]))
throw new Kohana_Database_Exception('database.must_use_table');

$table = $this->from[0];
}

// If caching is enabled, clear the cache before inserting
($this->config['cache'] === TRUE) and $this->clear_cache();

$sql = $this->driver->insert($this->config['table_prefix'].$table, array_keys($this->set), array_values($this->set));

$this->reset_write();

return $this->query($sql);
}

/**
* Adds an "IN" condition to the where clause
*
* @param string Name of the column being examined
* @param mixed An array or string to match against
* @param bool Generate a NOT IN clause instead
* @return Database This Database object.
*/
public function in($field, $values, $not = FALSE)
{
if (is_array($values))
{
$escaped_values = array();
foreach ($values as $v)
{
if (is_numeric($v))
{
$escaped_values[] = $v;
}
else
{
$escaped_values[] = "'".$this->driver->escape_str($v)."'";
}
}
$values = implode(",", $escaped_values);
}

$where = $this->driver->escape_column(((strpos($field,'.') !== FALSE) ? $this->config['table_prefix'] : ''). $field).' '.($not === TRUE ? 'NOT ' : '').'IN ('.$values.')';
$this->where[] = $this->driver->where($where, '', 'AND ', count($this->where), -1);

return $this;
}

/**
* Adds a "NOT IN" condition to the where clause
*
* @param string Name of the column being examined
* @param mixed An array or string to match against
* @return Database This Database object.
*/
public function notin($field, $values)
{
return $this->in($field, $values, TRUE);
}

/**
* Compiles a merge string and runs the query.
*
* @param string table name
* @param array array of key/value pairs to merge
* @return Database_Result Query result
*/
public function merge($table = '', $set = NULL)
{
if ( ! is_null($set))
{
$this->set($set);
}

if ($this->set == NULL)
throw new Kohana_Database_Exception('database.must_use_set');

if ($table == '')
{
if ( ! isset($this->from[0]))
throw new Kohana_Database_Exception('database.must_use_table');

$table = $this->from[0];
}

$sql = $this->driver->merge($this->config['table_prefix'].$table, array_keys($this->set), array_values($this->set));

$this->reset_write();
return $this->query($sql);
}

/**
* Compiles an update string and runs the query.
*
* @param string table name
* @param array associative array of update values
* @param array where clause
* @return Database_Result Query result
*/
public function update($table = '', $set = NULL, $where = NULL)
{
if ( is_array($set))
{
$this->set($set);
}

if ( ! is_null($where))
{
$this->where($where);
}

if ($this->set == FALSE)
throw new Kohana_Database_Exception('database.must_use_set');

if ($table == '')
{
if ( ! isset($this->from[0]))
throw new Kohana_Database_Exception('database.must_use_table');

$table = $this->from[0];
}

$sql = $this->driver->update($this->config['table_prefix'].$table, $this->set, $this->where);

$this->reset_write();
return $this->query($sql);
}

/**
* Compiles a delete string and runs the query.
*
* @param string table name
* @param array where clause
* @return Database_Result Query result
*/
public function delete($table = '', $where = NULL)
{
if ($table == '')
{
if ( ! isset($this->from[0]))
throw new Kohana_Database_Exception('database.must_use_table');

$table = $this->from[0];
}
else
{
$table = $this->config['table_prefix'].$table;
}

if (! is_null($where))
{
$this->where($where);
}

if (count($this->where) < 1)
throw new Kohana_Database_Exception('database.must_use_where');

$sql = $this->driver->delete($table, $this->where);

$this->reset_write();
return $this->query($sql);
}

/**
* Returns the last query run.
*
* @return string SQL
*/
public function last_query()
{
return $this->last_query;
}

/**
* Count query records.
*
* @param string table name
* @param array where clause
* @return integer
*/
public function count_records($table = FALSE, $where = NULL)
{
if (count($this->from) < 1)
{
if ($table == FALSE)
throw new Kohana_Database_Exception('database.must_use_table');

$this->from($table);
}

if ($where !== NULL)
{
$this->where($where);
}

$query = $this->select('COUNT(*) AS '.$this->escape_column('records_found'))->get()->result(TRUE);

return (int) $query->current()->records_found;
}

/**
* Resets all private select variables.
*
* @return void
*/
protected function reset_select()
{
$this->select = array();
$this->from = array();
$this->join = array();
$this->where = array();
$this->orderby = array();
$this->groupby = array();
$this->having = array();
$this->distinct = FALSE;
$this->limit = FALSE;
$this->offset = FALSE;
}

/**
* Resets all private insert and update variables.
*
* @return void
*/
protected function reset_write()
{
$this->set = array();
$this->from = array();
$this->where = array();
}

/**
* Lists all the tables in the current database.
*
* @return array
*/
public function list_tables()
{
$this->link or $this->connect();

return $this->driver->list_tables();
}

/**
* See if a table exists in the database.
*
* @param string table name
* @param boolean True to attach table prefix
* @return boolean
*/
public function table_exists($table_name, $prefix = TRUE)
{
if ($prefix)
return in_array($this->config['table_prefix'].$table_name, $this->list_tables());
else
return in_array($table_name, $this->list_tables());
}

/**
* Combine a SQL statement with the bind values. Used for safe queries.
*
* @param string query to bind to the values
* @param array array of values to bind to the query
* @return string
*/
public function compile_binds($sql, $binds)
{
foreach ((array) $binds as $val)
{
// If the SQL contains no more bind marks ("?"), we're done.
if (($next_bind_pos = strpos($sql, '?')) === FALSE)
break;

// Properly escape the bind value.
$val = $this->driver->escape($val);

// Temporarily replace possible bind marks ("?"), in the bind value itself, with a placeholder.
$val = str_replace('?', '{%B%}', $val);

// Replace the first bind mark ("?") with its corresponding value.
$sql = substr($sql, 0, $next_bind_pos).$val.substr($sql, $next_bind_pos + 1);
}

// Restore placeholders.
return str_replace('{%B%}', '?', $sql);
}

/**
* Get the field data for a database table, along with the field's attributes.
*
* @param string table name
* @return array
*/
public function field_data($table = '')
{
$this->link or $this->connect();

return $this->driver->field_data($this->config['table_prefix'].$table);
}

/**
* Get the field data for a database table, along with the field's attributes.
*
* @param string table name
* @return array
*/
public function list_fields($table = '')
{
$this->link or $this->connect();

return $this->driver->list_fields($this->config['table_prefix'].$table);
}

/**
* Escapes a value for a query.
*
* @param mixed value to escape
* @return string
*/
public function escape($value)
{
return $this->driver->escape($value);
}

/**
* Escapes a string for a query.
*
* @param string string to escape
* @return string
*/
public function escape_str($str)
{
return $this->driver->escape_str($str);
}

/**
* Escapes a table name for a query.
*
* @param string string to escape
* @return string
*/
public function escape_table($table)
{
return $this->driver->escape_table($table);
}

/**
* Escapes a column name for a query.
*
* @param string string to escape
* @return string
*/
public function escape_column($table)
{
return $this->driver->escape_column($table);
}

/**
* Returns table prefix of current configuration.
*
* @return string
*/
public function table_prefix()
{
return $this->config['table_prefix'];
}

/**
* Clears the query cache.
*
* @param string|TRUE clear cache by SQL statement or TRUE for last query
* @return Database This Database object.
*/
public function clear_cache($sql = NULL)
{
if ($sql === TRUE)
{
$this->driver->clear_cache($this->last_query);
}
elseif (is_string($sql))
{
$this->driver->clear_cache($sql);
}
else
{
$this->driver->clear_cache();
}

return $this;
}

/**
* Pushes existing query space onto the query stack. Use push
* and pop to prevent queries from clashing before they are
* executed
*
* @return Database This Databaes object
*/
public function push()
{
array_push($this->query_history, array(
$this->select,
$this->from,
$this->join,
$this->where,
$this->orderby,
$this->order,
$this->groupby,
$this->having,
$this->distinct,
$this->limit,
$this->offset
));

$this->reset_select();

return $this;
}

/**
* Pops from query stack into the current query space.
*
* @return Database This Databaes object
*/
public function pop()
{
if (count($this->query_history) == 0)
{
// No history
return $this;
}

list(
$this->select,
$this->from,
$this->join,
$this->where,
$this->orderby,
$this->order,
$this->groupby,
$this->having,
$this->distinct,
$this->limit,
$this->offset
) = array_pop($this->query_history);

return $this;
}

/**
* Count the number of records in the last query, without LIMIT or OFFSET applied.
*
* @return integer
*/
public function count_last_query()
{
if ($sql = $this->last_query())
{
if (stripos($sql, 'LIMIT') !== FALSE)
{
// Remove LIMIT from the SQL
$sql = preg_replace('/\sLIMIT\s+[^a-z]+/i', ' ', $sql);
}

if (stripos($sql, 'OFFSET') !== FALSE)
{
// Remove OFFSET from the SQL
$sql = preg_replace('/\sOFFSET\s+\d+/i', '', $sql);
}

// Get the total rows from the last query executed
$result = $this->query
(
'SELECT COUNT(*) AS '.$this->escape_column('total_rows').' '.
'FROM ('.trim($sql).') AS '.$this->escape_table('counted_results')
);

// Return the total number of rows from the query
return (int) $result->current()->total_rows;
}

return FALSE;
}
/**
* Sets benchmark on or off
*
* @author Ondřej Fibich
* @param boolean $is_on
*/
public function set_benchmark($is_on)
{
$this->config['benchmark'] = ($is_on === TRUE);
}

} // End Database Class


/**
* Sets the code for a Database exception.
*/
class Kohana_Database_Exception extends Kohana_Exception {

protected $code = E_DATABASE_ERROR;

} // End Kohana Database Exception
(5-5/22)