<?php
/**
 * PostgreSQL layer for DBO.
 *
 * PHP versions 4 and 5
 *
 * CakePHP(tm) : Rapid Development Framework (http://cakephp.org)
 * Copyright 2005-2010, Cake Software Foundation, Inc. (http://cakefoundation.org)
 *
 * Licensed under The MIT License
 * Redistributions of files must retain the above copyright notice.
 *
 * @copyright     Copyright 2005-2010, Cake Software Foundation, Inc. (http://cakefoundation.org)
 * @link          http://cakephp.org CakePHP(tm) Project
 * @package       cake
 * @subpackage    cake.cake.libs.model.datasources.dbo
 * @since         CakePHP(tm) v 0.9.1.114
 * @license       MIT License (http://www.opensource.org/licenses/mit-license.php)
 */

/**
 * PostgreSQL layer for DBO.
 *
 * Long description for class
 *
 * @package       cake
 * @subpackage    cake.cake.libs.model.datasources.dbo
 */
class DboPostgres extends DboSource {

/**
 * Driver description
 *
 * @var string
 * @access public
 */
	public $description = "PostgreSQL DBO Driver";

/**
 * Index of basic SQL commands
 *
 * @var array
 * @access protected
 */
	protected $_commands = array(
		'begin'    => 'BEGIN',
		'commit'   => 'COMMIT',
		'rollback' => 'ROLLBACK'
	);

/**
 * Base driver configuration settings.  Merged with user settings.
 *
 * @var array
 * @access protected
 */
	protected $_baseConfig = array(
		'persistent' => true,
		'host' => 'localhost',
		'login' => 'root',
		'password' => '',
		'database' => 'cake',
		'schema' => 'public',
		'port' => 5432,
		'encoding' => ''
	);

	public $columns = array(
		'primary_key' => array('name' => 'serial NOT NULL'),
		'string' => array('name'  => 'varchar', 'limit' => '255'),
		'text' => array('name' => 'text'),
		'integer' => array('name' => 'integer', 'formatter' => 'intval'),
		'float' => array('name' => 'float', 'formatter' => 'floatval'),
		'datetime' => array('name' => 'timestamp', 'format' => 'Y-m-d H:i:s', 'formatter' => 'date'),
		'timestamp' => array('name' => 'timestamp', 'format' => 'Y-m-d H:i:s', 'formatter' => 'date'),
		'time' => array('name' => 'time', 'format' => 'H:i:s', 'formatter' => 'date'),
		'date' => array('name' => 'date', 'format' => 'Y-m-d', 'formatter' => 'date'),
		'binary' => array('name' => 'bytea'),
		'boolean' => array('name' => 'boolean'),
		'number' => array('name' => 'numeric'),
		'inet' => array('name'  => 'inet')
	);

/**
 * Starting Quote
 *
 * @var string
 * @access public
 */
	public $startQuote = '"';

/**
 * Ending Quote
 *
 * @var string
 * @access public
 */
	public $endQuote = '"';

/**
 * Contains mappings of custom auto-increment sequences, if a table uses a sequence name
 * other than what is dictated by convention.
 *
 * @var array
 */
	protected $_sequenceMap = array();

/**
 * Connects to the database using options in the given configuration array.
 *
 * @return True if successfully connected.
 */
	function connect() {
		$config = $this->config;
		$conn  = "host='{$config['host']}' port='{$config['port']}' dbname='{$config['database']}' ";
		$conn .= "user='{$config['login']}' password='{$config['password']}'";

		if (!$config['persistent']) {
			$this->connection = pg_connect($conn, PGSQL_CONNECT_FORCE_NEW);
		} else {
			$this->connection = pg_pconnect($conn);
		}
		$this->connected = false;

		if ($this->connection) {
			$this->connected = true;
			$this->_execute("SET search_path TO " . $config['schema']);
		}
		if (!empty($config['encoding'])) {
			$this->setEncoding($config['encoding']);
		}
		return $this->connected;
	}

/**
 * Check if PostgreSQL is enabled/loaded
 *
 * @return boolean
 */
	function enabled() {
		return extension_loaded('pgsql');
	}
/**
 * Disconnects from database.
 *
 * @return boolean True if the database could be disconnected, else false
 */
	function disconnect() {
		if ($this->hasResult()) {
			pg_free_result($this->_result);
		}
		if (is_resource($this->connection)) {
			$this->connected = !pg_close($this->connection);
		} else {
			$this->connected = false;
		}
		return !$this->connected;
	}

/**
 * Executes given SQL statement.
 *
 * @param string $sql SQL statement
 * @return resource Result resource identifier
 */
	function _execute($sql) {
		return pg_query($this->connection, $sql);
	}

/**
 * Returns an array of tables in the database. If there are no tables, an error is raised and the application exits.
 *
 * @return array Array of tablenames in the database
 */
	function listSources() {
		$cache = parent::listSources();

		if ($cache != null) {
			return $cache;
		}

		$schema = $this->config['schema'];
		$sql = "SELECT table_name as name FROM INFORMATION_SCHEMA.tables WHERE table_schema = '{$schema}';";
		$result = $this->fetchAll($sql, false);

		if (!$result) {
			return array();
		} else {
			$tables = array();

			foreach ($result as $item) {
				$tables[] = $item[0]['name'];
			}

			parent::listSources($tables);
			return $tables;
		}
	}

/**
 * Returns an array of the fields in given table name.
 *
 * @param string $tableName Name of database table to inspect
 * @return array Fields in table. Keys are name and type
 */
	function &describe(&$model) {
		$fields = parent::describe($model);
		$table = $this->fullTableName($model, false);
		$this->_sequenceMap[$table] = array();

		if ($fields === null) {
			$cols = $this->fetchAll(
				"SELECT DISTINCT column_name AS name, data_type AS type, is_nullable AS null,
					column_default AS default, ordinal_position AS position, character_maximum_length AS char_length,
					character_octet_length AS oct_length FROM information_schema.columns
				WHERE table_name = " . $this->value($table) . " AND table_schema = " .
				$this->value($this->config['schema'])."  ORDER BY position",
				false
			);

			foreach ($cols as $column) {
				$colKey = array_keys($column);

				if (isset($column[$colKey[0]]) && !isset($column[0])) {
					$column[0] = $column[$colKey[0]];
				}

				if (isset($column[0])) {
					$c = $column[0];

					if (!empty($c['char_length'])) {
						$length = intval($c['char_length']);
					} elseif (!empty($c['oct_length'])) {
						if ($c['type'] == 'character varying') {
							$length = null;
							$c['type'] = 'text';
						} else {
							$length = intval($c['oct_length']);
						}
					} else {
						$length = $this->length($c['type']);
					}
					$fields[$c['name']] = array(
						'type'    => $this->column($c['type']),
						'null'    => ($c['null'] == 'NO' ? false : true),
						'default' => preg_replace(
							"/^'(.*)'$/",
							"$1",
							preg_replace('/::.*/', '', $c['default'])
						),
						'length'  => $length
					);
					if ($c['name'] == $model->primaryKey) {
						$fields[$c['name']]['key'] = 'primary';
						if ($fields[$c['name']]['type'] !== 'string') {
							$fields[$c['name']]['length'] = 11;
						}
					}
					if (
						$fields[$c['name']]['default'] == 'NULL' ||
						preg_match('/nextval\([\'"]?([\w.]+)/', $c['default'], $seq)
					) {
						$fields[$c['name']]['default'] = null;
						if (!empty($seq) && isset($seq[1])) {
							$this->_sequenceMap[$table][$c['name']] = $seq[1];
						}
					}
				}
			}
			$this->__cacheDescription($table, $fields);
		}
		if (isset($model->sequence)) {
			$this->_sequenceMap[$table][$model->primaryKey] = $model->sequence;
		}
		return $fields;
	}

/**
 * Returns a quoted and escaped string of $data for use in an SQL statement.
 *
 * @param string $data String to be prepared for use in an SQL statement
 * @param string $column The column into which this data will be inserted
 * @param boolean $read Value to be used in READ or WRITE context
 * @return string Quoted and escaped
 * @todo Add logic that formats/escapes data based on column type
 */
	function value($data, $column = null, $read = true) {

		$parent = parent::value($data, $column);
		if ($parent != null) {
			return $parent;
		}

		if ($data === null || (is_array($data) && empty($data))) {
			return 'NULL';
		}
		if (empty($column)) {
			$column = $this->introspectType($data);
		}

		switch($column) {
			case 'inet':
			case 'float':
			case 'integer':
			case 'date':
			case 'datetime':
			case 'timestamp':
			case 'time':
				if ($data === '') {
					return $read ? 'NULL' : 'DEFAULT';
				}
			case 'binary':
				$data = pg_escape_bytea($data);
			break;
			case 'boolean':
				if ($data === true || $data === 't' || $data === 'true') {
					return 'TRUE';
				} elseif ($data === false || $data === 'f' || $data === 'false') {
					return 'FALSE';
				}
				return (!empty($data) ? 'TRUE' : 'FALSE');
			break;
			default:
				$data = pg_escape_string($data);
			break;
		}
		return "'" . $data . "'";
	}

/**
 * Returns a formatted error message from previous database operation.
 *
 * @return string Error message
 */
	function lastError() {
		$error = pg_last_error($this->connection);
		return ($error) ? $error : null;
	}

/**
 * Returns number of affected rows in previous database operation. If no previous operation exists, this returns false.
 *
 * @return integer Number of affected rows
 */
	function lastAffected() {
		return ($this->_result) ? pg_affected_rows($this->_result) : false;
	}

/**
 * Returns number of rows in previous resultset. If no previous resultset exists,
 * this returns false.
 *
 * @return integer Number of rows in resultset
 */
	function lastNumRows() {
		return ($this->_result) ? pg_num_rows($this->_result) : false;
	}

/**
 * Returns the ID generated from the previous INSERT operation.
 *
 * @param string $source Name of the database table
 * @param string $field Name of the ID database field. Defaults to "id"
 * @return integer
 */
	function lastInsertId($source, $field = 'id') {
		$seq = $this->getSequence($source, $field);
		$data = $this->fetchRow("SELECT currval('{$seq}') as max");
		return $data[0]['max'];
	}

/**
 * Gets the associated sequence for the given table/field
 *
 * @param mixed $table Either a full table name (with prefix) as a string, or a model object
 * @param string $field Name of the ID database field. Defaults to "id"
 * @return string The associated sequence name from the sequence map, defaults to "{$table}_{$field}_seq"
 */
	function getSequence($table, $field = 'id') {
		if (is_object($table)) {
			$table = $this->fullTableName($table, false);
		}
		if (isset($this->_sequenceMap[$table]) && isset($this->_sequenceMap[$table][$field])) {
			return $this->_sequenceMap[$table][$field];
		} else {
			return "{$table}_{$field}_seq";
		}
	}

/**
 * Deletes all the records in a table and drops all associated auto-increment sequences
 *
 * @param mixed $table A string or model class representing the table to be truncated
 * @param integer $reset If -1, sequences are dropped, if 0 (default), sequences are reset,
 *						and if 1, sequences are not modified
 * @return boolean	SQL TRUNCATE TABLE statement, false if not applicable.
 */
	public function truncate($table, $reset = 0) {
		if (parent::truncate($table)) {
			$table = $this->fullTableName($table, false);
			if (isset($this->_sequenceMap[$table]) && $reset !== 1) {
				foreach ($this->_sequenceMap[$table] as $field => $sequence) {
					if ($reset === 0) {
						$this->execute("ALTER SEQUENCE \"{$sequence}\" RESTART WITH 1");
					} elseif ($reset === -1) {
						$this->execute("DROP SEQUENCE IF EXISTS \"{$sequence}\"");
					}
				}
			}
			return true;
		}
		return false;
	}

/**
 * Prepares field names to be quoted by parent
 *
 * @param string $data
 * @return string SQL field
 */
	function name($data) {
		if (is_string($data)) {
			$data = str_replace('"__"', '__', $data);
		}
		return parent::name($data);
	}

/**
 * Generates the fields list of an SQL query.
 *
 * @param Model $model
 * @param string $alias Alias tablename
 * @param mixed $fields
 * @return array
 */
	function fields(&$model, $alias = null, $fields = array(), $quote = true) {
		if (empty($alias)) {
			$alias = $model->alias;
		}
		$fields = parent::fields($model, $alias, $fields, false);

		if (!$quote) {
			return $fields;
		}
		$count = count($fields);

		if ($count >= 1 && strpos($fields[0], 'COUNT(*)') === false) {
			$result = array();
			for ($i = 0; $i < $count; $i++) {
				if (!preg_match('/^.+\\(.*\\)/', $fields[$i]) && !preg_match('/\s+AS\s+/', $fields[$i])) {
					if (substr($fields[$i], -1) == '*') {
						if (strpos($fields[$i], '.') !== false && $fields[$i] != $alias . '.*') {
							$build = explode('.', $fields[$i]);
							$AssociatedModel = $model->{$build[0]};
						} else {
							$AssociatedModel = $model;
						}

						$_fields = $this->fields($AssociatedModel, $AssociatedModel->alias, array_keys($AssociatedModel->schema()));
						$result = array_merge($result, $_fields);
						continue;
					}

					$prepend = '';
					if (strpos($fields[$i], 'DISTINCT') !== false) {
						$prepend = 'DISTINCT ';
						$fields[$i] = trim(str_replace('DISTINCT', '', $fields[$i]));
					}

					if (strrpos($fields[$i], '.') === false) {
						$fields[$i] = $prepend . $this->name($alias) . '.' . $this->name($fields[$i]) . ' AS ' . $this->name($alias . '__' . $fields[$i]);
					} else {
						$build = explode('.', $fields[$i]);
						$fields[$i] = $prepend . $this->name($build[0]) . '.' . $this->name($build[1]) . ' AS ' . $this->name($build[0] . '__' . $build[1]);
					}
				} else {
					$fields[$i] = preg_replace_callback('/\(([\s\.\w]+)\)/',  array(&$this, '__quoteFunctionField'), $fields[$i]);
				}
				$result[] = $fields[$i];
			}
			return $result;
		}
		return $fields;
	}

/**
 * Auxiliary function to quote matched `(Model.fields)` from a preg_replace_callback call
 *
 * @param string matched string
 * @return string quoted strig
 * @access private
 */
	function __quoteFunctionField($match) {
		$prepend = '';
		if (strpos($match[1], 'DISTINCT') !== false) {
			$prepend = 'DISTINCT ';
			$match[1] = trim(str_replace('DISTINCT', '', $match[1]));
		}
		if (strpos($match[1], '.') === false) {
			$match[1] = $this->name($match[1]);
		} else {
			$parts = explode('.', $match[1]);
			if (!Set::numeric($parts)) {
				$match[1] = $this->name($match[1]);
			}
		}
		return '(' . $prepend .$match[1] . ')';
	}

/**
 * Returns an array of the indexes in given datasource name.
 *
 * @param string $model Name of model to inspect
 * @return array Fields in table. Keys are column and unique
 */
	function index($model) {
		$index = array();
		$table = $this->fullTableName($model, false);
		if ($table) {
			$indexes = $this->query("SELECT c2.relname, i.indisprimary, i.indisunique, i.indisclustered, i.indisvalid, pg_catalog.pg_get_indexdef(i.indexrelid, 0, true) as statement, c2.reltablespace
			FROM pg_catalog.pg_class c, pg_catalog.pg_class c2, pg_catalog.pg_index i
			WHERE c.oid  = (
				SELECT c.oid
				FROM pg_catalog.pg_class c LEFT JOIN pg_catalog.pg_namespace n ON n.oid = c.relnamespace
				WHERE c.relname ~ '^(" . $table . ")$'
					AND pg_catalog.pg_table_is_visible(c.oid)
					AND n.nspname ~ '^(" . $this->config['schema'] . ")$'
			)
			AND c.oid = i.indrelid AND i.indexrelid = c2.oid
			ORDER BY i.indisprimary DESC, i.indisunique DESC, c2.relname", false);
			foreach ($indexes as $i => $info) {
				$key = array_pop($info);
				if ($key['indisprimary']) {
					$key['relname'] = 'PRIMARY';
				}
				$col = array();
				preg_match('/\(([^\)]+)\)/', $key['statement'], $indexColumns);
				$parsedColumn = $indexColumns[1];
				if (strpos($indexColumns[1], ',') !== false) {
					$parsedColumn = explode(', ', $indexColumns[1]);
				}
				$index[$key['relname']]['unique'] = $key['indisunique'];
				$index[$key['relname']]['column'] = $parsedColumn;
			}
		}
		return $index;
	}

/**
 * Alter the Schema of a table.
 *
 * @param array $compare Results of CakeSchema::compare()
 * @param string $table name of the table
 * @access public
 * @return array
 */
	function alterSchema($compare, $table = null) {
		if (!is_array($compare)) {
			return false;
		}
		$out = '';
		$colList = array();
		foreach ($compare as $curTable => $types) {
			$indexes = $colList = array();
			if (!$table || $table == $curTable) {
				$out .= 'ALTER TABLE ' . $this->fullTableName($curTable) . " \n";
				foreach ($types as $type => $column) {
					if (isset($column['indexes'])) {
						$indexes[$type] = $column['indexes'];
						unset($column['indexes']);
					}
					switch ($type) {
						case 'add':
							foreach ($column as $field => $col) {
								$col['name'] = $field;
								$alter = 'ADD COLUMN '.$this->buildColumn($col);
								if (isset($col['after'])) {
									$alter .= ' AFTER '. $this->name($col['after']);
								}
								$colList[] = $alter;
							}
						break;
						case 'drop':
							foreach ($column as $field => $col) {
								$col['name'] = $field;
								$colList[] = 'DROP COLUMN '.$this->name($field);
							}
						break;
						case 'change':
							foreach ($column as $field => $col) {
								if (!isset($col['name'])) {
									$col['name'] = $field;
								}
								$fieldName = $this->name($field);

								$default = isset($col['default']) ? $col['default'] : null;
								$nullable = isset($col['null']) ? $col['null'] : null;
								unset($col['default'], $col['null']);
								$colList[] = 'ALTER COLUMN '. $fieldName .' TYPE ' . str_replace($fieldName, '', $this->buildColumn($col));

								if (isset($nullable)) {
									$nullable = ($nullable) ? 'DROP NOT NULL' : 'SET NOT NULL';
									$colList[] = 'ALTER COLUMN '. $fieldName .'  ' . $nullable;
								}

								if (isset($default)) {
									$colList[] = 'ALTER COLUMN '. $fieldName .'  SET DEFAULT ' . $this->value($default, $col['type']);
								} else {
									$colList[] = 'ALTER COLUMN '. $fieldName .'  DROP DEFAULT';
								}

							}
						break;
					}
				}
				if (isset($indexes['drop']['PRIMARY'])) {
					$colList[] = 'DROP CONSTRAINT ' . $curTable . '_pkey';
				}
				if (isset($indexes['add']['PRIMARY'])) {
					$cols = $indexes['add']['PRIMARY']['column'];
					if (is_array($cols)) {
						$cols = implode(', ', $cols);
					}
					$colList[] = 'ADD PRIMARY KEY (' . $cols . ')';
				}

				if (!empty($colList)) {
					$out .= "\t" . implode(",\n\t", $colList) . ";\n\n";
				} else {
					$out = '';
				}
				$out .= implode(";\n\t", $this->_alterIndexes($curTable, $indexes));
			}
		}
		return $out;
	}

/**
 * Generate PostgreSQL index alteration statements for a table.
 *
 * @param string $table Table to alter indexes for
 * @param array $new Indexes to add and drop
 * @return array Index alteration statements
 */
	function _alterIndexes($table, $indexes) {
		$alter = array();
		if (isset($indexes['drop'])) {
			foreach($indexes['drop'] as $name => $value) {
				$out = 'DROP ';
				if ($name == 'PRIMARY') {
					continue;
				} else {
					$out .= 'INDEX ' . $name;
				}
				$alter[] = $out;
			}
		}
		if (isset($indexes['add'])) {
			foreach ($indexes['add'] as $name => $value) {
				$out = 'CREATE ';
				if ($name == 'PRIMARY') {
					continue;
				} else {
					if (!empty($value['unique'])) {
						$out .= 'UNIQUE ';
					}
					$out .= 'INDEX ';
				}
				if (is_array($value['column'])) {
					$out .= $name . ' ON ' . $table . ' (' . implode(', ', array_map(array(&$this, 'name'), $value['column'])) . ')';
				} else {
					$out .= $name . ' ON ' . $table . ' (' . $this->name($value['column']) . ')';
				}
				$alter[] = $out;
			}
		}
		return $alter;
	}

/**
 * Returns a limit statement in the correct format for the particular database.
 *
 * @param integer $limit Limit of results returned
 * @param integer $offset Offset from which to start results
 * @return string SQL limit/offset statement
 */
	function limit($limit, $offset = null) {
		if ($limit) {
			$rt = '';
			if (!strpos(strtolower($limit), 'limit') || strpos(strtolower($limit), 'limit') === 0) {
				$rt = ' LIMIT';
			}

			$rt .= ' ' . $limit;
			if ($offset) {
				$rt .= ' OFFSET ' . $offset;
			}

			return $rt;
		}
		return null;
	}

/**
 * Converts database-layer column types to basic types
 *
 * @param string $real Real database-layer column type (i.e. "varchar(255)")
 * @return string Abstract column type (i.e. "string")
 */
	function column($real) {
		if (is_array($real)) {
			$col = $real['name'];
			if (isset($real['limit'])) {
				$col .= '(' . $real['limit'] . ')';
			}
			return $col;
		}

		$col = str_replace(')', '', $real);
		$limit = null;

		if (strpos($col, '(') !== false) {
			list($col, $limit) = explode('(', $col);
		}

		$floats = array(
			'float', 'float4', 'float8', 'double', 'double precision', 'decimal', 'real', 'numeric'
		);

		switch (true) {
			case (in_array($col, array('date', 'time', 'inet', 'boolean'))):
				return $col;
			case (strpos($col, 'timestamp') !== false):
				return 'datetime';
			case (strpos($col, 'time') === 0):
				return 'time';
			case (strpos($col, 'int') !== false && $col != 'interval'):
				return 'integer';
			case (strpos($col, 'char') !== false || $col == 'uuid'):
				return 'string';
			case (strpos($col, 'text') !== false):
				return 'text';
			case (strpos($col, 'bytea') !== false):
				return 'binary';
			case (in_array($col, $floats)):
				return 'float';
			default:
				return 'text';
			break;
		}
	}

/**
 * Gets the length of a database-native column description, or null if no length
 *
 * @param string $real Real database-layer column type (i.e. "varchar(255)")
 * @return int An integer representing the length of the column
 */
	function length($real) {
		$col = str_replace(array(')', 'unsigned'), '', $real);
		$limit = null;

		if (strpos($col, '(') !== false) {
			list($col, $limit) = explode('(', $col);
		}
		if ($col == 'uuid') {
			return 36;
		}
		if ($limit != null) {
			return intval($limit);
		}
		return null;
	}

/**
 * Enter description here...
 *
 * @param unknown_type $results
 */
	function resultSet(&$results) {
		$this->results =& $results;
		$this->map = array();
		$num_fields = pg_num_fields($results);
		$index = 0;
		$j = 0;

		while ($j < $num_fields) {
			$columnName = pg_field_name($results, $j);

			if (strpos($columnName, '__')) {
				$parts = explode('__', $columnName);
				$this->map[$index++] = array($parts[0], $parts[1]);
			} else {
				$this->map[$index++] = array(0, $columnName);
			}
			$j++;
		}
	}

/**
 * Fetches the next row from the current result set
 *
 * @return unknown
 */
	function fetchResult() {
		if ($row = pg_fetch_row($this->results)) {
			$resultRow = array();

			foreach ($row as $index => $field) {
				list($table, $column) = $this->map[$index];
				$type = pg_field_type($this->results, $index);

				switch ($type) {
					case 'bool':
						$resultRow[$table][$column] = $this->boolean($row[$index], false);
					break;
					case 'binary':
					case 'bytea':
						$resultRow[$table][$column] = pg_unescape_bytea($row[$index]);
					break;
					default:
						$resultRow[$table][$column] = $row[$index];
					break;
				}
			}
			return $resultRow;
		} else {
			return false;
		}
	}

/**
 * Translates between PHP boolean values and PostgreSQL boolean values
 *
 * @param mixed $data Value to be translated
 * @param boolean $quote	True to quote value, false otherwise
 * @return mixed Converted boolean value
 */
	function boolean($data, $quote = true) {
		switch (true) {
			case ($data === true || $data === false):
				return $data;
			case ($data === 't' || $data === 'f'):
				return ($data === 't');
			case ($data === 'true' || $data === 'false'):
				return ($data === 'true');
			case ($data === 'TRUE' || $data === 'FALSE'):
				return ($data === 'TRUE');
			default:
				return (bool)$data;
			break;
		}
	}

/**
 * Sets the database encoding
 *
 * @param mixed $enc Database encoding
 * @return boolean True on success, false on failure
 */
	function setEncoding($enc) {
		return pg_set_client_encoding($this->connection, $enc) == 0;
	}

/**
 * Gets the database encoding
 *
 * @return string The database encoding
 */
	function getEncoding() {
		return pg_client_encoding($this->connection);
	}

/**
 * Generate a Postgres-native column schema string
 *
 * @param array $column An array structured like the following:
 *                      array('name'=>'value', 'type'=>'value'[, options]),
 *                      where options can be 'default', 'length', or 'key'.
 * @return string
 */
	function buildColumn($column) {
		$col = $this->columns[$column['type']];
		if (!isset($col['length']) && !isset($col['limit'])) {
			unset($column['length']);
		}
		$out = preg_replace('/integer\([0-9]+\)/', 'integer', parent::buildColumn($column));
		$out = str_replace('integer serial', 'serial', $out);
		if (strpos($out, 'timestamp DEFAULT')) {
			if (isset($column['null']) && $column['null']) {
				$out = str_replace('DEFAULT NULL', '', $out);
			} else {
				$out = str_replace('DEFAULT NOT NULL', '', $out);
			}
		}
		if (strpos($out, 'DEFAULT DEFAULT')) {
			if (isset($column['null']) && $column['null']) {
				$out = str_replace('DEFAULT DEFAULT', 'DEFAULT NULL', $out);
			} elseif (in_array($column['type'], array('integer', 'float'))) {
				$out = str_replace('DEFAULT DEFAULT', 'DEFAULT 0', $out);
			} elseif ($column['type'] == 'boolean') {
				$out = str_replace('DEFAULT DEFAULT', 'DEFAULT FALSE', $out);
			}
		}
		return $out;
	}

/**
 * Format indexes for create table
 *
 * @param array $indexes
 * @param string $table
 * @return string
 */
	function buildIndex($indexes, $table = null) {
		$join = array();
		if (!is_array($indexes)) {
			return array();
		}
		foreach ($indexes as $name => $value) {
			if ($name == 'PRIMARY') {
				$out = 'PRIMARY KEY  (' . $this->name($value['column']) . ')';
			} else {
				$out = 'CREATE ';
				if (!empty($value['unique'])) {
					$out .= 'UNIQUE ';
				}
				if (is_array($value['column'])) {
					$value['column'] = implode(', ', array_map(array(&$this, 'name'), $value['column']));
				} else {
					$value['column'] = $this->name($value['column']);
				}
				$out .= "INDEX {$name} ON {$table}({$value['column']});";
			}
			$join[] = $out;
		}
		return $join;
	}

/**
 * Overrides DboSource::renderStatement to handle schema generation with Postgres-style indexes
 *
 * @param string $type
 * @param array $data
 * @return string
 */
	function renderStatement($type, $data) {
		switch (strtolower($type)) {
			case 'schema':
				extract($data);

				foreach ($indexes as $i => $index) {
					if (preg_match('/PRIMARY KEY/', $index)) {
						unset($indexes[$i]);
						$columns[] = $index;
						break;
					}
				}
				$join = array('columns' => ",\n\t", 'indexes' => "\n");

				foreach (array('columns', 'indexes') as $var) {
					if (is_array(${$var})) {
						${$var} = implode($join[$var], array_filter(${$var}));
					}
				}
				return "CREATE TABLE {$table} (\n\t{$columns}\n);\n{$indexes}";
			break;
			default:
				return parent::renderStatement($type, $data);
			break;
		}
	}
}