framework/db/pgsql/ColumnSchema.php
protected function phpTypecastValue($value)
    {
        if ($value === null) {
            return null;
        }

        switch ($this->type) {
            case Schema::TYPE_BOOLEAN:
                switch (strtolower($value)) {
                    case 't':
                    case 'true':
                        return true;
                    case 'f':
                    case 'false':
                        return false;
                }
                return (bool) $value;
            case Schema::TYPE_JSON:
                return $this->disableJsonSupport ? $value : json_decode($value, true);
        }

        return parent::phpTypecast($value);
    }
protected function phpTypecastValue($value)
    {
        if ($value === null) {
            return null;
        }

        switch ($this->type) {
            case Schema::TYPE_BOOLEAN:
                switch (strtolower($value)) {
                    case 't':
                    case 'true':
                        return true;
                    case 'f':
                    case 'false':
                        return false;
                }
                return (bool) $value;
            case Schema::TYPE_JSON:
                return $this->disableJsonSupport ? $value : json_decode($value, true);
        }

        return parent::phpTypecast($value);
    }
Casts $value after retrieving from the DBMS to PHP representation.

@param string|null $value
@return bool|mixed|null