protected $_type;//连接数据库的类型,默认使用MYSQL数据库

protected $_host;//数据库的IP地址，默认使用localhost表示本地

protected $_port;//数据库连接的端口号，默认使用3306

protected $_char;//设置的字符集，默认使用utf8

protected $_dbname;//需要选择的数据库名，默认使用db1数据库

protected $_acc;//连接数据库的帐号

protected $_pwd;//连接数据库的密码

protected $_pdo;//保存PDO类的对象的属性

protected $_pdostatement;//保存PDOStatement类的对象的属性

//用于连接操作

private $sql = '';

private $orderSql = '';

private $limitSql = '';

private $preSql = '';

// 2.0

private $_sql;

private $_table; // 数据表

private $_condition;// 条件

protected $_field = '*';

private $_join = '';

private $_limit = '';

private $_alias = '';

private $_order = '';

public function __construct($type='', $host='', $port='', $char='', $dbname='', $acc='', $pwd=''){

//初始化属性

$this->_type = empty($type) ? C('pdo.type') : $type;

$this->_host = empty($host) ? C('pdo.host') : $host;

$this->_port = empty($port) ? C('pdo.port') : $port;

$this->_char = empty($char) ? C('pdo.char') : $char;

$this->_dbname = empty($dbname) ? C('pdo.db') : $dbname;

$this->_acc = empty($acc) ? C('pdo.acc') : $acc;

$this->_pwd = empty($pwd) ? C('pdo.pwd') : $pwd;

//实例化PDO类的对象

$dsn = "{$this->_type}:host={$this->_host};port={$this->_port};charset={$this->_char};dbname={$this->_dbname}";

$this->_pdo = new \PDO($dsn, $this->_acc, $this->_pwd);

//开启异常错误处理模式

$this->_pdo->setAttribute(\PDO::ATTR_ERRMODE, \PDO::ERRMODE_EXCEPTION);

}

//错误信息输出方法

private function errMsg($err){

echo 'SQL语句：' . $this->_sql . "<br />";

echo '错误信息为：' . $err->getMessage() . '<br/>';

echo '出错的文件：' . $err->getFile() . '<br/>';

echo '在文件中出错的位置：' . $err->getLine();

exit;

}

//设置数据（增、删、改操作）

public function setData($sql){

try{

$this->_pdo->exec($sql);

}catch(\PDOException $aa){

$this->errMsg($aa);

}

return true;

}

//得到sql语句

public function getSql(){

return $this->preSql;

}

//连接操作

public function join($sql){

$this->_join .= "join {$sql} ";

$this->sql .= " join {$sql} ";

return $this;

}

//别名操作

public function alias($sql){

$this->_alias = " as {$sql} ";

$this->sql .= " as {$sql} ";

return $this;

}

public function order($sql){

$this->_order = " order by {$sql} ";

$this->orderSql .= " order by {$sql} ";

return $this;

}

public function limit($sql){

$this->_limit = " limit {$sql} ";

$this->limitSql .= " limit {$sql} ";

return $this;

}

//获得一条数据记录的方法

public function getRow($fields, $tbname, $condition){

$this->sql = $sql = "select {$fields} from {$tbname} {$this->sql} where {$condition} {$this->orderSql} limit 1";

$this->preSql = $this->sql;

try{

$this->_pdostatement = $this->_pdo->query($sql);//执行查询SQL语句

}catch(\PDOException $err){

$this->preSql = $this->sql;

$this->errMsg($err);//输出错误信息

}

$res = $this->_pdostatement->fetch(\PDO::FETCH_ASSOC);//解析一条记录并且作为返回值返回

$this->sql = '';

return $res;

}

//获得多条数据的方法

public function getRows($fields, $tbname, $condition){

$this->sql = $sql = "select {$fields} from {$tbname} {$this->sql} where {$condition} {$this->orderSql} {$this->limitSql}";

$this->preSql = $this->sql;

//var_dump($this->sql);

try{

$this->_pdostatement = $this->_pdo->query($sql);//执行查询SQL语句

}catch(\PDOException $err){

$this->preSql = $this->sql;

$this->errMsg($err);//输出错误信息

}

$res = $this->_pdostatement->fetchAll();//解析全部的记录并且作为返回值返回

$this->sql = '';

return $res;

}

public function getColumns($tbname){

$sql = "select * from {$tbname} limit 1";

$arr = array();

try{

$this->_pdostatement = $this->_pdo->query($sql);

$count = $this->_pdostatement->columnCount();

for($i = 0; $i < $count; $i++){

$arr[] = $this->_pdostatement->getColumnMeta($i);

}

}catch(\PDOException $err){

$this->errMsg($err);

}

return $arr;

}

/************************2.0*******************************/

public function field($str){

$this->_field = $str;

return $this;

}

public function table($str){

$this->_table = $str;

return $this;

}

private function _condition($condition){

$str = '';

foreach ($condition as $key => $val) {

if($str != '' && $val[0] != 'or'){

$str .= ' and ';

}

switch ($val) {

case is_string($val):

$str .= " $key = '$val' ";

break;

case is_numeric($val):

$str .= " $key = $val ";

break;

case is_array($val):

// [ 'id' => ['<', 123456] ]

if( is_array($val) ){

// [ 'id' => ['<', 123456] ]

if( is_array($val[0]) ){

// [ 'id' => ['<', 123456] ]

// [ 'id' => [ ['>', 123456], ['<', 123459] ]

foreach ($val as $k => $v) {

$str .= " $key {$v[0]} '$v[1]' ";

// echo $k . ' ' . (count($val) - 1) . "\n";

if( $k != count($val) - 1 ){

if( isset($v[2]) ){

$str .= $v[2];

}else{

$str .= ' and ';

}

}

}

}else{

$str .= " $key {$val[0]} '$val[1]' ";

}

}else{

$str .= " $key {$val[0]} '$val[1]' ";

}

break;

default:

$str .= " $key = '$val' ";

break;

}

}

$this->_condition = $str;

return $this;

}

public function getSql2(){

return $this->_sql;

}

public function select($condition = [], $type = ""){

if( !empty($condition) ){

$this->_condition($condition);

$this->_condition = 'where ' . $this->_condition;

}

$sql = "select {$this->_field} from {$this->_table} {$this->_alias} {$this->_join} {$this->_condition} {$this->_order} {$this->_limit}";

$this->_sql = $sql;

try{

$this->_pdostatement = $this->_pdo->query($sql);

}catch(\PDOException $err){

$this->errMsg($err);//输出错误信息

}

$PDOType = !empty($type) ? $type : \PDO::FETCH_ASSOC;

return $this->_pdostatement->fetchAll($PDOType);

}

public function find($condition = [], $type = ""){

if( !empty($condition) ){

$this->_condition($condition);

$this->_condition = 'where ' . $this->_condition;

}

$sql = "select {$this->_field} from {$this->_table} {$this->_condition}";

$this->_sql = $sql;

try{

$this->_pdostatement = $this->_pdo->query($sql);

}catch(\PDOException $err){

$this->errMsg($err);//输出错误信息

}

$PDOType = !empty($type) ? $type : \PDO::FETCH_ASSOC;

return $this->_pdostatement->fetch($PDOType);

}

private function _setData($data){

$str = '';

foreach ($data as $key => $val) {

if( $str != '' ){

$str .= ' , ';

}

if( is_string($val) ){

$str .= " $key = '$val' ";

}else if( is_numeric($val) ){

$str .= " $key = $val ";

}

}

return $str;

}

public function update($data, $condition = ''){

if( !empty($condition) ){

$this->_condition($condition);

$this->_condition = ' where ' . $this->_condition;

}

$data = $this->_setData($data);

$sql = "update {$this->_table} set {$data} {$this->_condition}";

try{

$this->_pdo->exec($sql);

}catch(\PDOException $err){

$this->errMsg($err);

}

return true;

}

public function insert($data){

$dataStr = $this->_setData($data);

$keyStr = "(";

$index = 1;

foreach ($data as $key => $val) {

if( $index != 1 ){

$keyStr .= ',';

}

$keyStr .= $key;

$index++;

}

$keyStr .= ")";

$dataStr = '(';

$index = 1;

foreach ($data as $key => $val) {

if( $index != 1 ){

$dataStr .= ',';

}

if( is_string($val) ){

$dataStr .= "'{$val}'";

}else if(is_numeric($val)){

$dataStr .= $val;

}

$index++;

}

$dataStr .= ")";

$sql = "insert into {$this->_table}{$keyStr} values{$dataStr}";

$this->_sql = $sql;

try{

$this->_pdo->exec($sql);

}catch(\PDOException $err){

$this->errMsg($err);

}

return true;

}

public function delete($condition){

if( !empty($condition) ){

$this->_condition($condition);

$this->_condition = 'where ' . $this->_condition;

}

$sql = "delete from {$this->_table} {$this->_condition}";

$this->_sql = $sql;

try{

$this->_pdostatement = $this->_pdo->query($sql);

}catch(\PDOException $err){

$this->errMsg($err);//输出错误信息

}

return true;

}