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<?php
/**
 * CakePHP(tm) : Rapid Development Framework (http://cakephp.org)
 * Copyright (c) Cake Software Foundation, Inc. (http://cakefoundation.org)
 *
 * Licensed under The MIT License
 * For full copyright and license information, please see the LICENSE.txt
 * Redistributions of files must retain the above copyright notice.
 *
 * @copyright     Copyright (c) Cake Software Foundation, Inc. (http://cakefoundation.org)
 * @link          http://cakephp.org CakePHP(tm) Project
 * @package       Cake.Model.Datasource.Database
 * @since         CakePHP(tm) v 0.9.1.114
 * @license       http://www.opensource.org/licenses/mit-license.php MIT License
 */

App::uses('DboSource', 'Model/Datasource');

/**
 * PostgreSQL layer for DBO.
 *
 * @package       Cake.Model.Datasource.Database
 */
class Postgres extends DboSource {

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

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

/**
 * Columns
 *
 * @var array
 */
        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'),
                'biginteger' => array('name' => 'bigint', 'limit' => '20'),
                'float' => array('name' => 'float', 'formatter' => 'floatval'),
                'decimal' => array('name' => 'decimal', '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
 */
        public $startQuote = '"';

/**
 * Ending Quote
 *
 * @var string
 */
        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();

/**
 * The set of valid SQL operations usable in a WHERE statement
 *
 * @var array
 */
        protected $_sqlOps = array('like', 'ilike', 'or', 'not', 'in', 'between', '~', '~\*', '\!~', '\!~\*', 'similar to');

/**
 * Connects to the database using options in the given configuration array.
 *
 * @return bool True if successfully connected.
 * @throws MissingConnectionException
 */
        public function connect() {
                $config = $this->config;
                $this->connected = false;

                $flags = $config['flags'] + array(
                        PDO::ATTR_PERSISTENT => $config['persistent'],
                        PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION
                );

                try {
                        $this->_connection = new PDO(
                                "pgsql:host={$config['host']};port={$config['port']};dbname={$config['database']};sslmode={$config['sslmode']}",
                                $config['login'],
                                $config['password'],
                                $flags
                        );

                        $this->connected = true;
                        if (!empty($config['encoding'])) {
                                $this->setEncoding($config['encoding']);
                        }
                        if (!empty($config['schema'])) {
                                $this->_execute('SET search_path TO "' . $config['schema'] . '"');
                        }
                        if (!empty($config['settings'])) {
                                foreach ($config['settings'] as $key => $value) {
                                        $this->_execute("SET $key TO $value");
                                }
                        }
                } catch (PDOException $e) {
                        throw new MissingConnectionException(array(
                                'class' => get_class($this),
                                'message' => $e->getMessage()
                        ));
                }

                return $this->connected;
        }

/**
 * Check if PostgreSQL is enabled/loaded
 *
 * @return bool
 */
        public function enabled() {
                return in_array('pgsql', PDO::getAvailableDrivers());
        }

/**
 * Returns an array of tables in the database. If there are no tables, an error is raised and the application exits.
 *
 * @param mixed $data The sources to list.
 * @return array Array of table names in the database
 */
        public function listSources($data = null) {
                $cache = parent::listSources();

                if ($cache) {
                        return $cache;
                }

                $schema = $this->config['schema'];
                $sql = "SELECT table_name as name FROM INFORMATION_SCHEMA.tables WHERE table_schema = ?";
                $result = $this->_execute($sql, array($schema));

                if (!$result) {
                        return array();
                }

                $tables = array();

                foreach ($result as $item) {
                        $tables[] = $item->name;
                }

                $result->closeCursor();
                parent::listSources($tables);
                return $tables;
        }

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

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

                        // @codingStandardsIgnoreStart
                        // Postgres columns don't match the coding standards.
                        foreach ($cols as $c) {
                                $type = $c->type;
                                if (!empty($c->oct_length) && $c->char_length === null) {
                                        if ($c->type === 'character varying') {
                                                $length = null;
                                                $type = 'text';
                                        } elseif ($c->type === 'uuid') {
                                                $length = 36;
                                        } else {
                                                $length = (int)$c->oct_length;
                                        }
                                } elseif (!empty($c->char_length)) {
                                        $length = (int)$c->char_length;
                                } else {
                                        $length = $this->length($c->type);
                                }
                                if (empty($length)) {
                                        $length = null;
                                }
                                $fields[$c->name] = array(
                                        'type' => $this->column($type),
                                        'null' => ($c->null === 'NO' ? false : true),
                                        'default' => preg_replace(
                                                "/^'(.*)'$/",
                                                "$1",
                                                preg_replace('/::.*/', '', $c->default)
                                        ),
                                        'length' => $length
                                );
                                if ($model instanceof Model) {
                                        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' ||
                                        $c->default === null ||
                                        preg_match('/nextval\([\'"]?([\w.]+)/', $c->default, $seq)
                                ) {
                                        $fields[$c->name]['default'] = null;
                                        if (!empty($seq) && isset($seq[1])) {
                                                if (strpos($seq[1], '.') === false) {
                                                        $sequenceName = $c->schema . '.' . $seq[1];
                                                } else {
                                                        $sequenceName = $seq[1];
                                                }
                                                $this->_sequenceMap[$table][$c->name] = $sequenceName;
                                        }
                                }
                                if ($fields[$c->name]['type'] === 'timestamp' && $fields[$c->name]['default'] === '') {
                                        $fields[$c->name]['default'] = null;
                                }
                                if ($fields[$c->name]['type'] === 'boolean' && !empty($fields[$c->name]['default'])) {
                                        $fields[$c->name]['default'] = constant($fields[$c->name]['default']);
                                }
                        }
                        $this->_cacheDescription($table, $fields);
                }
                // @codingStandardsIgnoreEnd

                if (isset($model->sequence)) {
                        $this->_sequenceMap[$table][$model->primaryKey] = $model->sequence;
                }

                if ($cols) {
                        $cols->closeCursor();
                }
                return $fields;
        }

/**
 * Returns the ID generated from the previous INSERT operation.
 *
 * @param string $source Name of the database table
 * @param string $field Name of the ID database field. Defaults to "id"
 * @return int
 */
        public function lastInsertId($source = null, $field = 'id') {
                $seq = $this->getSequence($source, $field);
                return $this->_connection->lastInsertId($seq);
        }

/**
 * Gets the associated sequence for the given table/field
 *
 * @param string|Model $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}_{$field}_seq"
 */
        public function getSequence($table, $field = 'id') {
                if (is_object($table)) {
                        $table = $this->fullTableName($table, false, false);
                }
                if (!isset($this->_sequenceMap[$table])) {
                        $this->describe($table);
                }
                if (isset($this->_sequenceMap[$table][$field])) {
                        return $this->_sequenceMap[$table][$field];
                }
                return "{$table}_{$field}_seq";
        }

/**
 * Reset a sequence based on the MAX() value of $column. Useful
 * for resetting sequences after using insertMulti().
 *
 * @param string $table The name of the table to update.
 * @param string $column The column to use when resetting the sequence value,
 *   the sequence name will be fetched using Postgres::getSequence();
 * @return bool success.
 */
        public function resetSequence($table, $column) {
                $tableName = $this->fullTableName($table, false, false);
                $fullTable = $this->fullTableName($table);

                $sequence = $this->value($this->getSequence($tableName, $column));
                $column = $this->name($column);
                $this->execute("SELECT setval($sequence, (SELECT MAX($column) FROM $fullTable))");
                return true;
        }

/**
 * Deletes all the records in a table and drops all associated auto-increment sequences
 *
 * @param string|Model $table A string or model class representing the table to be truncated
 * @param bool $reset true for resetting the sequence, false to leave it as is.
 *    and if 1, sequences are not modified
 * @return bool SQL TRUNCATE TABLE statement, false if not applicable.
 */
        public function truncate($table, $reset = false) {
                $table = $this->fullTableName($table, false, false);
                if (!isset($this->_sequenceMap[$table])) {
                        $cache = $this->cacheSources;
                        $this->cacheSources = false;
                        $this->describe($table);
                        $this->cacheSources = $cache;
                }
                if ($this->execute('DELETE FROM ' . $this->fullTableName($table))) {
                        if (isset($this->_sequenceMap[$table]) && $reset != true) {
                                foreach ($this->_sequenceMap[$table] as $sequence) {
                                        $quoted = $this->name($sequence);
                                        $this->_execute("ALTER SEQUENCE {$quoted} RESTART WITH 1");
                                }
                        }
                        return true;
                }
                return false;
        }

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

/**
 * Generates the fields list of an SQL query.
 *
 * @param Model $model The model to get fields for.
 * @param string $alias Alias table name.
 * @param mixed $fields The list of fields to get.
 * @param bool $quote Whether or not to quote identifiers.
 * @return array
 */
        public function fields(Model $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 && !preg_match('/^\s*COUNT\(\*/', $fields[0])) {
                        $result = array();
                        for ($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
 * Quotes the fields in a function call.
 *
 * @param string $match matched string
 * @return string quoted string
 */
        protected function _quoteFunctionField($match) {
                $prepend = '';
                if (strpos($match[1], 'DISTINCT') !== false) {
                        $prepend = 'DISTINCT ';
                        $match[1] = trim(str_replace('DISTINCT', '', $match[1]));
                }
                $constant = preg_match('/^\d+|NULL|FALSE|TRUE$/i', $match[1]);

                if (!$constant && strpos($match[1], '.') === false) {
                        $match[1] = $this->name($match[1]);
                } elseif (!$constant) {
                        $parts = explode('.', $match[1]);
                        if (!Hash::numeric($parts)) {
                                $match[1] = $this->name($match[1]);
                        }
                }
                return '(' . $prepend . $match[1] . ')';
        }

/**
 * Returns an array of the indexes in given datasource name.
 *
 * @param string $model Name of model to inspect
 * @return array Fields in table. Keys are column and unique
 */
        public function index($model) {
                $index = array();
                $table = $this->fullTableName($model, false, 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 $info) {
                                $key = array_pop($info);
                                if ($key['indisprimary']) {
                                        $key['relname'] = 'PRIMARY';
                                }
                                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 $table name of the table
 * @return array
 */
        public function alterSchema($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;
                                                                $colList[] = 'ADD COLUMN ' . $this->buildColumn($col);
                                                        }
                                                        break;
                                                case 'drop':
                                                        foreach ($column as $field => $col) {
                                                                $col['name'] = $field;
                                                                $colList[] = 'DROP COLUMN ' . $this->name($field);
                                                        }
                                                        break;
                                                case 'change':
                                                        $schema = $this->describe($curTable);
                                                        foreach ($column as $field => $col) {
                                                                if (!isset($col['name'])) {
                                                                        $col['name'] = $field;
                                                                }
                                                                $original = $schema[$field];
                                                                $fieldName = $this->name($field);

                                                                $default = isset($col['default']) ? $col['default'] : null;
                                                                $nullable = isset($col['null']) ? $col['null'] : null;
                                                                $boolToInt = $original['type'] === 'boolean' && $col['type'] === 'integer';
                                                                unset($col['default'], $col['null']);
                                                                if ($field !== $col['name']) {
                                                                        $newName = $this->name($col['name']);
                                                                        $out .= "\tRENAME {$fieldName} TO {$newName};\n";
                                                                        $out .= 'ALTER TABLE ' . $this->fullTableName($curTable) . " \n";
                                                                        $fieldName = $newName;
                                                                }

                                                                if ($boolToInt) {
                                                                        $colList[] = 'ALTER COLUMN ' . $fieldName . '  SET DEFAULT NULL';
                                                                        $colList[] = 'ALTER COLUMN ' . $fieldName . ' TYPE ' . str_replace(array($fieldName, 'NOT NULL'), '', $this->buildColumn($col)) . ' USING CASE WHEN TRUE THEN 1 ELSE 0 END';
                                                                } else {
                                                                        if ($original['type'] === 'text' && $col['type'] === 'integer') {
                                                                                $colList[] = 'ALTER COLUMN ' . $fieldName . ' TYPE ' . str_replace(array($fieldName, 'NOT NULL'), '', $this->buildColumn($col)) . " USING cast({$fieldName} as INTEGER)";
                                                                        } else {
                                                                                $colList[] = 'ALTER COLUMN ' . $fieldName . ' TYPE ' . str_replace(array($fieldName, 'NOT NULL'), '', $this->buildColumn($col));
                                                                        }
                                                                }

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

                                                                if (isset($default)) {
                                                                        if (!$boolToInt) {
                                                                                $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 $indexes Indexes to add and drop
 * @return array Index alteration statements
 */
        protected function _alterIndexes($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 int $limit Limit of results returned
 * @param int $offset Offset from which to start results
 * @return string SQL limit/offset statement
 */
        public function limit($limit, $offset = null) {
                if ($limit) {
                        $rt = sprintf(' LIMIT %u', $limit);
                        if ($offset) {
                                $rt .= sprintf(' OFFSET %u', $offset);
                        }
                        return $rt;
                }
                return null;
        }

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

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

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

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

                switch (true) {
                        case (in_array($col, array('date', 'time', 'inet', 'boolean'))):
                                return $col;
                        case (strpos($col, 'timestamp') !== false):
                                return 'datetime';
                        case (strpos($col, 'time') === 0):
                                return 'time';
                        case ($col === 'bigint'):
                                return 'biginteger';
                        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($col, 'bytea') !== false):
                                return 'binary';
                        case ($col === 'decimal' || $col === 'numeric'):
                                return 'decimal';
                        case (in_array($col, $floats)):
                                return 'float';
                        default:
                                return 'text';
                }
        }

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

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

/**
 * resultSet method
 *
 * @param array &$results The results
 * @return void
 */
        public function resultSet(&$results) {
                $this->map = array();
                $numFields = $results->columnCount();
                $index = 0;
                $j = 0;

                while ($j < $numFields) {
                        $column = $results->getColumnMeta($j);
                        if (strpos($column['name'], '__')) {
                                list($table, $name) = explode('__', $column['name']);
                                $this->map[$index++] = array($table, $name, $column['native_type']);
                        } else {
                                $this->map[$index++] = array(0, $column['name'], $column['native_type']);
                        }
                        $j++;
                }
        }

/**
 * Fetches the next row from the current result set
 *
 * @return array
 */
        public function fetchResult() {
                if ($row = $this->_result->fetch(PDO::FETCH_NUM)) {
                        $resultRow = array();

                        foreach ($this->map as $index => $meta) {
                                list($table, $column, $type) = $meta;

                                switch ($type) {
                                        case 'bool':
                                                $resultRow[$table][$column] = $row[$index] === null ? null : $this->boolean($row[$index]);
                                                break;
                                        case 'binary':
                                        case 'bytea':
                                                $resultRow[$table][$column] = $row[$index] === null ? null : stream_get_contents($row[$index]);
                                                break;
                                        default:
                                                $resultRow[$table][$column] = $row[$index];
                                }
                        }
                        return $resultRow;
                }
                $this->_result->closeCursor();
                return false;
        }

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

                if ($quote) {
                        return ($result) ? 'TRUE' : 'FALSE';
                }
                return (bool)$result;
        }

/**
 * Sets the database encoding
 *
 * @param mixed $enc Database encoding
 * @return bool True on success, false on failure
 */
        public function setEncoding($enc) {
                return $this->_execute('SET NAMES ' . $this->value($enc)) !== false;
        }

/**
 * Gets the database encoding
 *
 * @return string The database encoding
 */
        public function getEncoding() {
                $result = $this->_execute('SHOW client_encoding')->fetch();
                if ($result === false) {
                        return false;
                }
                return (isset($result['client_encoding'])) ? $result['client_encoding'] : false;
        }

/**
 * Generate a Postgres-native column schema string
 *
 * @param array $column An array structured like the following:
 *                      array('name'=>'value', 'type'=>'value'[, options]),
 *                      where options can be 'default', 'length', or 'key'.
 * @return string
 */
        public function buildColumn($column) {
                $col = $this->columns[$column['type']];
                if (!isset($col['length']) && !isset($col['limit'])) {
                        unset($column['length']);
                }
                $out = parent::buildColumn($column);

                $out = preg_replace(
                        '/integer\([0-9]+\)/',
                        'integer',
                        $out
                );
                $out = preg_replace(
                        '/bigint\([0-9]+\)/',
                        'bigint',
                        $out
                );

                $out = str_replace('integer serial', 'serial', $out);
                $out = str_replace('bigint serial', 'bigserial', $out);
                if (strpos($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 The index to build
 * @param string $table The table name.
 * @return string
 */
        public function buildIndex($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 The query type.
 * @param array $data The array of data to render.
 * @return string
 */
        public function renderStatement($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{$indexes}";
                        default:
                                return parent::renderStatement($type, $data);
                }
        }

/**
 * Gets the schema name
 *
 * @return string The schema name
 */
        public function getSchemaName() {
                return $this->config['schema'];
        }

/**
 * Check if the server support nested transactions
 *
 * @return bool
 */
        public function nestedTransactionSupported() {
                return $this->useNestedTransactions && version_compare($this->getVersion(), '8.0', '>=');
        }

}