class db{
/**
* 定义数据库连接
*/
/**
* return 返回一个值叫做链式调用
*每执行完一个方法就会返回当前对象
*返回的对象 可以调用类中的成员变量和成员方法
*/
protected $mysqli; //连接工具
protected $table; //数据表
protected $opt; //存储条件
function __construct($table_name){ //定义一个数据库连接
$this->config($table_name);
}
protected function config($table_name){
$this->mysqli=new mysqli(HOST, USER, PWD, DBBASE);
$this->table=$table_name; //表名
if(mysqli_connect_errno()){
echo "数据库连接错误".mysqli_connect_erron();
exit();
}
$this->mysqli->query("set names 'latin1'");
$this->opt['filed']="*"; //设置默认查询字段
$this->opt['where']=$this->opt['limit']=$this->opt['order']=$this->opt['group']=' '; //设置他们的条件都为空
}
/**
* 获取表的字段
*/
function fileds(){
$result=$this->mysqli->query("DESC{$this->table}"); //查询表结构
$filedsarray=array();
while ($rows=$result->fetch_assoc()!=false){ //循环字段关联数组
$filedsarray[]=$rows['Field'];
}
return $filedsarray;
}
/**
* 查询表的字段
*
*/
function filed($filed){
/*首先$filed就是字段 查询的字段 首先判断获取的字段是否是字符串
*
*/
if (is_string($filed)){
$filedarry=explode(",", $filed); /*分割字符串*/
}else{
$filedarry=$filed;
}
if(is_array($filedarry)){
$filed="";
foreach ($filedarry as $v){
$filed .= "`" . $v . "`" . ",";
}
}
return rtrim($filed,",");
}
/**
* 条件方法where
*/
function where($where){
if(is_string($where)){
$this->opt['where']="WHERE".$where;
}else{
$this->opt['where']="";
}
return $this;
}
/**
* limit 条件
*/
function limit($limit){
if(is_string($limit)){
$this->opt['limit']="LIMIT".$limit;
}else{
$this->opt['limit']="";
}
return $this;
}
/**
* order by 条件
*/
function order($order){
if (is_string($order)){
$this->opt['order']="ORDER BY".$order;
}else{
$this->opt['order']="";
}
return $this;
}
/**
* group by 调教
*/
function group($group){
if (is_string($group)){
$this->opt['group']="GROUP BY".$group;
}else{
$this->opt['group']="";
}
return $this;
}
/**
* select语句查询
*/
function select(){
/**
* $sql=select * from 表名 where limiy order by group by
*/
$sql="SELECT {$this->opt['filed']} FROM {$this->table} {$this->opt['where']}{$this->opt['order']}{$this->opt['group']}{$this->opt['limit']}";
return $this->sql($sql);
}
/**
* delete 删除语句
*/
function delate($id=""){
if($id==""&&empty($this->opt['where'])) die ("获取的查询条件不能为空");
if($id!=""){
if(is_array($id)){
$id=implode(",",$id);/*implode 将获取的数组分割成字符串 每分割一个加个逗号*/
}
$this->opt['where']="WHERE id IN(".$id.")";
}
/*delete from 表名 where 条件*/
$sql="DELETE FROM {$this->table} {$this->opt['where']} {$this->opt['limit']}";
echo $sql."<br/>";
return $this->query($sql);
}
/**
* 返回sql语句结果集
*/
function sql($sql) {
$result = $this->mysqli
->query ( $sql ) or die ( $this->dbError () );
$resultArr = array ();
while ( ($row = $result->fetch_assoc ()) != false ) {
$resultArr [] = $row;
}
return $resultArr;
}
/**
* insert语句
*/
function insert($ins){
is_array($ins) or die("非法数组");
$fileds=$this->filed(array_keys($ins));
var_dump($fileds);
$values=$this->values(array_values($ins));
var_dump($values);
$sql="INSERT INTO {$this->table}(".$fileds.") VALUES(".$values.")";
if($this->query($sql)>0){
return $this->mysqli->insert_id;
}
}
/**
* 将数组转换字符串并进行转义
*/
protected function values($value){
if (!get_magic_quotes_gpc()){
$str="";
foreach ($value as $v){
$str.="'".addslashes($v)."',";
}
}else{
foreach ($value as $v){
$str.="'.$v.',";
}
}
return rtrim($str,",");
}
/**
* 没有结果集
*/
function query($sql){
$this->mysqli->query($sql)or die($this->error());
return $this->mysqli->affected_rows; //返回前一个 Mysql 操作的受影响行数
}
/**
* update 更新语句
* update biao set 列明=新值 where 列明=某值
*/
function update($up){
is_array($sql)or die("非法字符串");
if (empty($this->opt['where'])) die("条件不能为空");
$set="";
$gpc=get_magic_quotes_gpc();
while (list($k,$v)=each($up)){
$v = ! $gpc ? addslashes ( $v ) : $v;
$set .= "`{$k}`='" . $v . "',";
}
$set=rtrim($set,",");
$sql="UPDATE {$this->table} SET $set {$this->opt['where']}";
return $this->query($sql);
}
/**
* 查寻总记录记录数
*/
function count($tablename=""){
$tabname = $tabname == '' ? $this->table : $tabname;
$sql = "SELECT `id` FROM {$tabname} {$this->opt['where']}";
return $this->query ( $sql );
}
/**
* 查询单机路数
*/
function find($id){
$sql = "SELECT {$this->opt['field']} FROM {$this->table} WHERE `id` = {$id}";
return $this->sql ( $sql );
}
/**
* 返回错误
*/
function error(){
return $this->mysqli->error;
}
}
