<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
/**
* CodeIgniter
*
* An open source application development framework for PHP 5.1.6 or newer
*
* @package CodeIgniter
* @author ExpressionEngine Dev Team
* @copyright Copyright (c) 2008 - 2011, EllisLab, Inc.
* @license http://codeigniter.com/user_guide/license.html
* @link http://codeigniter.com
* @since Version 1.0
* @filesource
*/
// ------------------------------------------------------------------------
/**
* Postgre Database Adapter Class
* Postgre数据库适配器类
*
* Note: _DB is an extender class that the app controller
* creates dynamically based on whether the active record
* class is being used or not.
* 注：_DB是一个扩展类的应用程序控制器
* 创建动态的基础上是否活动记录
* 类正在使用与否。
*
* @package CodeIgniter
* @subpackage Drivers
* @category Database
* @author ExpressionEngine Dev Team
* @link http://codeigniter.com/user_guide/database/
*/
class CI_DB_postgre_driver extends CI_DB
{
//数据库类型
var $dbdriver = 'postgre';
var $_escape_char = '"';
// clause and character used for LIKE escape sequences
// 子句和LIKE转义序列字符用于
var $_like_escape_str = " ESCAPE '%s' ";
var $_like_escape_chr = '!';
/**
* The syntax to count rows is slightly different across different
* database engines, so this string appears in each driver and is
* used for the count_all() and count_all_results() functions.
* 在不同的数行的语法略有不同
* 数据库引擎，所以这个字符串出现在每个驱动器和
* 用于count_all（）和count_all_results（）函数。
*
*/
var $_count_string = "SELECT COUNT(*) AS ";
var $_random_keyword = ' RANDOM()'; // database specific random keyword
/**
* Connection String
* 连接字符串
* @access private
* @return string
*/
function _connect_string()
{
$components = array(
'hostname' => 'host',
'port' => 'port',
'database' => 'dbname',
'username' => 'user',
'password' => 'password'
);
$connect_string = "";
foreach ($components as $key => $val)
{
if (isset($this->$key) && $this->$key != '')
{
$connect_string .= " $val=".$this->$key;
}
}
return trim($connect_string);
}
// --------------------------------------------------------------------
/**
* Non-persistent database connection
* 非持久性数据库连接
* @access private called by the base class 私人称为基类
* @return resource
*/
function db_connect()
{
//pg_connect();
return @pg_connect($this->_connect_string());
}
// --------------------------------------------------------------------
/**
* Persistent database connection
* 持久性数据库连接
* @access private called by the base class
* @return resource
*/
function db_pconnect()
{
//pg_pconnect();
return @pg_pconnect($this->_connect_string());
}
// --------------------------------------------------------------------
/**
* Reconnect
* 重新连接
*
* Keep / reestablish the db connection if no queries have been
* sent for a length of time exceeding the server's idle timeout
*
* 保持/重新建立数据库连接，如果没有查询
* 发送的时间长度超过服务器的空闲超时
*
* @access public
* @return void
*/
function reconnect()
{
//如果pg_ping()这个连接资源已经不存在
if (pg_ping($this->conn_id) === FALSE)
{
$this->conn_id = FALSE;
}
}
// --------------------------------------------------------------------
/**
* Select the database
* 选择数据库
* @access private called by the base class
* @return resource
*/
function db_select()
{
// Not needed for Postgre so we'll return
// TRUE Postgre并不需要，所以我们就返回TRUE
return TRUE;
}
// --------------------------------------------------------------------
/**
* Set client character set
* 设置字符串设置
*
* @access public
* @param string
* @param string
* @return resource
*/
function db_set_charset($charset, $collation)
{
// @todo - add support if needed //postgre 不需要这个
return TRUE;
}
// --------------------------------------------------------------------
/**
* Version number query string
* 版本信息
*
* @access public
* @return string
*/
function _version()
{
return "SELECT version() AS ver";
}
// --------------------------------------------------------------------
/**
* Execute the query
* 执行查询
* @access private called by the base class 要求由基类
* @param string an SQL query
* @return resource
*/
function _execute($sql)
{
$sql = $this->_prep_query($sql);
return @pg_query($this->conn_id, $sql);
}
// --------------------------------------------------------------------
/**
* Prep the query
* 准备查询
* If needed, each database adapter can prep the query string
* 如果需要，每个数据库适配器可以预先准备的查询字符串
* @access private called by execute()
* @param string an SQL query
* @return string
*/
function _prep_query($sql)
{
return $sql;
}
// --------------------------------------------------------------------
/**
* Begin Transaction
* 开始交易
*
* @access public
* @return bool
*/
function trans_begin($test_mode = FALSE)
{
//如果trans_enabled为真
if ( ! $this->trans_enabled)
{
return TRUE;
}
// When transactions are nested we only begin/commit/rollback the outermost ones
// 当事务被嵌套，我们才开始/提交/回滚最外层的
if ($this->_trans_depth > 0)
{
return TRUE;
}
// Reset the transaction failure flag.
// If the $test_mode flag is set to TRUE transactions will be rolled back
// even if the queries produce a successful result.
// 复位的交易失败标志。
// 如果$ TEST_MODE标志设置为TRUE交易将回滚
// 即使查询产生一个成功的结果。
$this->_trans_failure = ($test_mode === TRUE) ? TRUE : FALSE;
//pg_exec($this->conn_id, "begin"); 开始
return @pg_exec($this->conn_id, "begin");
}
// --------------------------------------------------------------------
/**
* Commit Transaction
* pg_exec -- 向服务器发送一个查询字串
* @access public
* @return bool
*/
function trans_commit()
{
if ( ! $this->trans_enabled)
{
return TRUE;
}
// When transactions are nested we only begin/commit/rollback the outermost ones
// 当事务被嵌套，我们才开始/提交/回滚最外层的
if ($this->_trans_depth > 0)
{
return TRUE;
}
return @pg_exec($this->conn_id, "commit");
}
// --------------------------------------------------------------------
/**
* Rollback Transaction
* 回滚
* @access public
* @return bool
*/
function trans_rollback()
{
if ( ! $this->trans_enabled)
{
return TRUE;
}
// When transactions are nested we only begin/commit/rollback the outermost ones
if ($this->_trans_depth > 0)
{
return TRUE;
}
return @pg_exec($this->conn_id, "rollback");
}
// --------------------------------------------------------------------
/**
* Escape String
*
* @access public
* @param string
* @param bool whether or not the string will be used in a LIKE condition
* 是否该字符串将被用于在LIKE条件
* @return string
*/
function escape_str($str, $like = FALSE)
{
//是否为数组
if (is_array($str))
{
//开始循环，开始递归
foreach ($str as $key => $val)
{
$str[$key] = $this->escape_str($val, $like);
}
return $str;
}
$str = pg_escape_string($str);
//pg_escape_string() 转义 text/char 数据类型的字符串，返回转义后的字符串。建议用此函数替代 addslashes()。
//pg_escape_string() 转义text/char 数据类型的字符串，返回转义后的字符串
// escape LIKE condition wildcards
// 逃离LIKE条件通配符
if ($like === TRUE)
{
$str = str_replace( array('%', '_', $this->_like_escape_chr),
array($this->_like_escape_chr.'%', $this->_like_escape_chr.'_', $this->_like_escape_chr.$this->_like_escape_chr),
$str);
}
return $str;
}
// --------------------------------------------------------------------
/**
* Affected Rows
* 受影响的行
* @access public
* @return integer
*/
function affected_rows()
{
return @pg_affected_rows($this->result_id);
}
// --------------------------------------------------------------------
/**
* Insert ID
* 获取插入记录的id
* @access public
* @return integer
*/
function insert_id()
{
$v = $this->_version();
$v = $v['server'];
//取得表名
$table = func_num_args() > 0 ? func_get_arg(0) : NULL;
//行
$column = func_num_args() > 1 ? func_get_arg(1) : NULL;
//表名为空，并且版本大于8.1
if ($table == NULL && $v >= '8.1')
{
$sql='SELECT LASTVAL() as ins_id';
}
//如果表名不为表，列不为空，版本大于8.0时
elseif ($table != NULL && $column != NULL && $v >= '8.0')
{
$sql = sprintf("SELECT pg_get_serial_sequence('%s','%s') as seq", $table, $column);
$query = $this->query($sql);
$row = $query->row();
$sql = sprintf("SELECT CURRVAL('%s') as ins_id", $row->seq);
}
elseif ($table != NULL)
{
// seq_name passed in table parameter
$sql = sprintf("SELECT CURRVAL('%s') as ins_id", $table);
}
else
{
return pg_last_oid($this->result_id);
}
$query = $this->query($sql);
$row = $query->row();
return $row->ins_id;
}
// --------------------------------------------------------------------
/**
* "Count All" query
* “伯爵所有”查询
* Generates a platform-specific query string that counts all records in
* the specified database
* 生成一个平台特定的查询字符串中的所有记录计数
* 指定的数据库
*
* @access public
* @param string
* @return string
*/
function count_all($table = '')
{
if ($table == '')
{
return 0;
}
$query = $this->query($this->_count_string . $this->_protect_identifiers('numrows') . " FROM " . $this->_protect_identifiers($table, TRUE, NULL, FALSE));
if ($query->num_rows() == 0)
{
return 0;
}
$row = $query->row();
$this->_reset_select();
return (int) $row->numrows;
}
// --------------------------------------------------------------------
/**
* Show table query
* 显示表查询
* Generates a platform-specific query string so that the table names can be fetched
* 生成一个特定于平台的查询字符串，以便可以获取表名
* @access private
* @param boolean
* @return string
*/
function _list_tables($prefix_limit = FALSE)
{
$sql = "SELECT table_name FROM information_schema.tables WHERE table_schema = 'public'";
if ($prefix_limit !== FALSE AND $this->dbprefix != '')
{
$sql .= " AND table_name LIKE '".$this->escape_like_str($this->dbprefix)."%' ".sprintf($this->_like_escape_str, $this->_like_escape_chr);
}
return $sql;
}
// --------------------------------------------------------------------
/**
* Show column query
* 显示列查询
* Generates a platform-specific query string so that the column names can be fetched
* 生成一个特定于平台的查询字符串，以便可以获取列名
* @access public
* @param string the table name
* @return string
*/
function _list_columns($table = '')
{
return "SELECT column_name FROM information_schema.columns WHERE table_name ='".$table."'";
}
// --------------------------------------------------------------------
/**
* Field data query
* 现场数据查询
* Generates a platform-specific query so that the column data can be retrieved
* 生成一个特定于平台的查询，以便可以检索的列数据
* @access public
* @param string the table name
* @return object
*/
function _field_data($table)
{
return "SELECT * FROM ".$table." LIMIT 1";
}
// --------------------------------------------------------------------
/**
* The error message string
* 该错误消息字符串
* @access private
* @return string
*/
function _error_message()
{
//pg_last_error()
return pg_last_error($this->conn_id);
}
// --------------------------------------------------------------------
/**
* The error message number
*
* @access private
* @return integer
*/
function _error_number()
{
return '';
}
// --------------------------------------------------------------------
/**
* Escape the SQL Identifiers
* 逃离SQL标识符
* This function escapes column and table names
* 此功能逃脱列和表名
* @access private
* @param string
* @return string
*/
function _escape_identifiers($item)
{
if ($this->_escape_char == '')
{
return $item;
}
foreach ($this->_reserved_identifiers as $id)
{
//如果在$item中能找到$id的字符，
if (strpos($item, '.'.$id) !== FALSE)
{
//
$str = $this->_escape_char. str_replace('.', $this->_escape_char.'.', $item);
// remove duplicates if the user already included the escape
// 删除重复，如果用户已经逃逸
return preg_replace('/['.$this->_escape_char.']+/', $this->_escape_char, $str);
}
}
if (strpos($item, '.') !== FALSE)
{
$str = $this->_escape_char.str_replace('.', $this->_escape_char.'.'.$this->_escape_char, $item).$this->_escape_char;
}
else
{
$str = $this->_escape_char.$item.$this->_escape_char;
}
// remove duplicates if the user already included the escape
// 删除重复，如果用户已经逃逸
return preg_replace('/['.$this->_escape_char.']+/', $this->_escape_char, $str);
}
// --------------------------------------------------------------------
/**
* From Tables
* 从表
* This function implicitly groups FROM tables so there is no confusion
* about operator precedence in harmony with SQL standards
* 此功能隐含团队从表所以没有混乱
* 运算符优先级在和谐与SQL标准
* @access public
* @param type
* @return type
*/
function _from_tables($tables)
{
if ( ! is_array($tables))
{
$tables = array($tables);
}
return implode(', ', $tables);
}
// --------------------------------------------------------------------
/**
* Insert statement
* 插入语句
*
* Generates a platform-specific insert string from the supplied data
*
* @access public
* @param string the table name
* @param array the insert keys
* @param array the insert values
* @return string
*/
function _insert($table, $keys, $values)
{
return "INSERT INTO ".$table." (".implode(', ', $keys).") VALUES (".implode(', ', $values).")";
}
// --------------------------------------------------------------------
/**
* Insert_batch statement
* 批量插入????
*
* Generates a platform-specific insert string from the supplied data
*
* @access public
* @param string the table name
* @param array the insert keys
* @param array the insert values
* @return string
*/
function _insert_batch($table, $keys, $values)
{
return "INSERT INTO ".$table." (".implode(', ', $keys).") VALUES ".implode(', ', $values);
}
// --------------------------------------------------------------------
/**
* Update statement
* 更新?
* Generates a platform-specific update string from the supplied data
*
* @access public
* @param string the table name
* @param array the update data
* @param array the where clause
* @param array the orderby clause
* @param array the limit clause
* @return string
*/
function _update($table, $values, $where, $orderby = array(), $limit = FALSE)
{
//需要更新的值
foreach ($values as $key => $val)
{
$valstr[] = $key." = ".$val;
}
//更新的记录条数
$limit = ( ! $limit) ? '' : ' LIMIT '.$limit;
//排序
$orderby = (count($orderby) >= 1)?' ORDER BY '.implode(", ", $orderby):'';
//拼接成update 语句
$sql = "UPDATE ".$table." SET ".implode(', ', $valstr);
//添加where 条件
$sql .= ($where != '' AND count($where) >=1) ? " WHERE ".implode(" ", $where) : '';
$sql .= $orderby.$limit;
return $sql;
}
// --------------------------------------------------------------------
/**
* Truncate statement
* 截断语句
*
* Generates a platform-specific truncate string from the supplied data
* If the database does not support the truncate() command
* This function maps to "DELETE FROM table"
*
* 从所提供的数据，生成一个特定于平台的截断字符串
* 如果数据库不支持的截断（）命令。
* 此功能映射到“DELETE FROM表”
* @access public
* @param string the table name
* @return string
*/
function _truncate($table)
{
return "TRUNCATE ".$table;
}
// --------------------------------------------------------------------
/**
* Delete statement
* 删除表
* Generates a platform-specific delete string from the supplied data
*
* @access public
* @param string the table name
* @param array the where clause
* @param string the limit clause
* @return string
*/
function _delete($table, $where = array(), $like = array(), $limit = FALSE)
{
$conditions = '';
//where条件
//$like 这个$where 好像没多大做的，用的是$this->ar_where;
if (count($where) > 0 OR count($like) > 0)
{
$conditions = "\nWHERE ";
$conditions .= implode("\n", $this->ar_where);
if (count($where) > 0 && count($like) > 0)
{
$conditions .= " AND ";
}
$conditions .= implode("\n", $like);
}
//数量
$limit = ( ! $limit) ? '' : ' LIMIT '.$limit;
return "DELETE FROM ".$table.$conditions.$limit;
}
// --------------------------------------------------------------------
/**
* Limit string
*
* Generates a platform-specific LIMIT clause
*
* @access public
* @param string the sql query string
* @param integer the number of rows to limit the query to
* @param integer the offset value
* @return string
*/
function _limit($sql, $limit, $offset)
{
$sql .= "LIMIT ".$limit;
if ($offset > 0)
{
$sql .= " OFFSET ".$offset;
}
return $sql;
}
// --------------------------------------------------------------------
/**
* Close DB Connection
* 关闭
* @access public
* @param resource
* @return void
*/
function _close($conn_id)
{
@pg_close($conn_id);
}
}
/* End of file postgre_driver.php */
/* Location: ./system/database/drivers/postgre/postgre_driver.php */
浙公网安备 33010602011771号