简单易用的php数据库pdo操作类(curd demo)

<?php
class db_api
{
    // 数据库表名
    protected $table;
    // 数据库主键
    protected $primary = 'id';
    // 表前缀
    protected $prefix = '';
    // where和order拼装后的条件
    private $filter = array();
    // pdo
    private $pdo;
    // pdostatement
    private $statement;
    // pdo链接数据库
    public function __construct($config){
        class_exists('pdo') or exit("not found pdo");
        try{
            $this->pdo = new pdo("mysql:host=".$config['db_host'].";port=".$config['db_port'].";dbname=".$config['db_name'],$config['db_user'], $config['db_pass']); 
        }catch(pdoexception $e){
            // 数据库无法链接，如果您是第一次使用，请先配置数据库！
            exit($e->getmessage());
        }
        $this->prefix = $config['db_prefix'];
        $this->pdo->exec("set names utf8");
    }
    // 配置表信息
    public function set_table($table=null,$primary='id'){
        if($table==null){ exit('not found table');}
        $this->primary = $primary;
        $this->table = $this->prefix.$table;
        return $this;
    }
    // 获取数据
    public function getdata($sql)
    {
        if(!$result = $this->query($sql))return array();
        if(!$this->statement->rowcount())return array();
        $rows = array();
        while($rows[] = $this->statement->fetch(pdo::fetch_assoc)){}
        $this->statement=null;
        array_pop($rows);
        return $rows;
    }
    // 查询数据条数
    public function getcount($conditions){
        $where = '';
        if(is_array($conditions)){
            $join = array();
            foreach( $conditions as $key => $value ){
                $value =  '\''.$value.'\'';
                $join[] = "{$key} = {$value}";
            }
            $where = "where ".join(" and ",$join);
        }else{
            if(null != $conditions)$where = "where ".$conditions;
        }
        $sql = "select count(*) as frcount from {$this->table} {$where}";
        $result = $this->getdata($sql);
        return $result[0]['frcount'];
    }
    // 获取单一字段内容
    public function getfield($where=null,$fields=null){
        if( $record = $this->findall($where, null, $fields, 1) ){
            $res = array_pop($record);
            return $res[$fields];
        }else{
            return false;
        }
    }
    // 递增数据
    public function goinc($conditions,$field,$vp=1){
        $where = "";
        if(is_array($conditions)){
            $join = array();
            foreach( $conditions as $key => $value ){
                $value = '\''.$value.'\'';
                $join[] = "{$key} = {$value}";
            }
            $where = "where ".join(" and ",$join);
        }else{
            if(null != $conditions)$where = "where ".$conditions;
        }
        $values = "{$field} = {$field} + {$vp}";
        $sql = "update {$this->table} set {$values} {$where}";
        return $this->pdo->exec($sql);
    }
    // 递减
    public function godec($conditions,$field,$vp=1){
        return $this->goinc($conditions,$field,-$vp);
    }
    // 修改数据
    public function update($conditions,$row)
    {
        $where = "";
        $row = $this->__prepera_format($row);
        if(empty($row)){
        return false;
        }
        if(is_array($conditions)){
            $join = array();
            foreach( $conditions as $key => $condition ){
                $condition = '\''.$condition.'\'';
                $join[] = "{$key} = {$condition}";
            }
            $where = "where ".join(" and ",$join);
        }else{
            if(null != $conditions){
              $where = "where ".$conditions;
            }
        }
        foreach($row as $key => $value){
            $value = '\''.$value.'\'';
            $vals[] = "{$key} = {$value}";
        }
        $values = join(", ",$vals);
        $sql = "update {$this->table} set {$values} {$where}";
        //echo $sql.'<br/>';
        $res = $this->pdo->exec($sql);
      if($res){
          return $res;
      }else{
          var_dump($this->pdo->errorinfo());
      }
    }
    // 查询所有
    public function findall($conditions=null,$order=null,$fields=null,$limit=null)
    {
        $where = '';
        if(is_array($conditions)){
            $join = array();
            foreach( $conditions as $key => $value ){
                $value =  '\''.$value.'\'';
                $join[] = "{$key} = {$value}";
            }
            $where = "where ".join(" and ",$join);
        }else{
            if(null != $conditions)$where = "where ".$conditions;
        }
      if(is_array($order)){
               $where .= ' order by ';
            $where .= implode(',', $order);
      }else{
         if($order!=null)$where .= " order by  ".$order;
      }
        if(!empty($limit))$where .= " limit {$limit}";
        $fields = empty($fields) ? "*" : $fields;
        $sql = "select {$fields} from {$this->table} {$where}";
        return $this->getdata($sql);
    }
    // 查询一条
    public function find($where=null,$order=null,$fields=null,$limit=1)
    {
       if( $record = $this->findall($where, $order, $fields, 1) ){
            return array_pop($record);
        }else{
            return false;
        }
    }
    // 执行sql语句并检查是否错误
    public function query($sql){
        $this->filter[] = $sql;
        $this->statement = $this->pdo->query($sql);
        if ($this->statement) {
            return $this;
        }else{
            $msg = $this->pdo->errorinfo();
            if($msg[2]) exit('数据库错误：' . $msg[2] . end($this->filter));
        }
    }
    // 执行sql语句函数
    public function findsql($sql)
    {
        return $this->getdata($sql);
    }
    // 根据条件 (conditions) 删除
    public function delete($conditions)
    {
       $where = "";
        if(is_array($conditions)){
            $join = array();
            foreach( $conditions as $key => $condition ){
                $condition = '\''.$condition.'\'';
                $join[] = "{$key} = {$condition}";
            }
            $where = "where ( ".join(" and ",$join). ")";
        }else{
            if(null != $conditions)$where = "where ( ".$conditions. ")";
        }
        $sql = "delete from {$this->table} {$where}";
        return $this->pdo->exec($sql);
    }
    // 新增数据
    public function add($row)
    {
       if(!is_array($row)){
         return false;
       }
        $row = $this->__prepera_format($row);
        if(empty($row)){
         return false;
        }
        foreach($row as $key => $value){
            $cols[] = $key;
            $vals[] = '\''.$value.'\'';
        }
        $col = join(',', $cols);
        $val = join(',', $vals);
        $sql = "insert into {$this->table} ({$col}) values ({$val})";
        if( false != $this->pdo->exec($sql) ){
            if( $newinserid = $this->pdo->lastinsertid() ){
                return $newinserid;
            }else{
                $a=$this->find($row, "{$this->primary} desc",$this->primary);
                return array_pop($a);
            }
        }
        return false;
    }
    private function __prepera_format($rows)
    {
        $stmt = $this->pdo->prepare('desc '.$this->table);  
        $stmt->execute();  
        $columns = $stmt->fetchall(pdo::fetch_column);
        $newcol = array();
        foreach( $columns as $col ){
            $newcol[$col] = null;
        }
        return array_intersect_key($rows,$newcol);
    }
}

<?php
header("content-type:text/html;charset=utf-8");
// 引入类
include './db.class.php';
// 数据库配置
$config  = [
    'db_host' => 'localhost', // 数据库地址
    'db_port' => 3306, // 默认mysql数据库端口
    'db_name' => 'test', // 数据库名字
    'db_user' => 'root', // 数据库用户名
    'db_pass' => 'root', // 数据库密码
    'db_prefix' => '', // 表前缀
];
// 实例化类
$db = new db_api($config);
// 表名
$article = $db->set_table('article');
// 新增数据
$newdata = ['title'=>'this is a title'];
$r = $article->add($newdata);
if($r){
    echo '新增成功！';
}else{
    echo '操作失败！';
}
// 查询数据
$where = ['id'=>3];
$find = $article->find($where); //查询一条数据
$find = $article->findall($where); // 查询多条数据
print_r($find);
// 更新数据
$updatadata = ['title'=>'hello world is updated']; // 要修改的数据
$where = ['id'=>1]; // 条件
$update = $article->update($where, $updatadata);
if($update ){
    echo '更新成功！';
    // 查询并打印
    $newdata = $article->find('id=1');
    print_r($newdata);
}else{
    echo '更新失败！';
}
// 删除数据
$where = ['id'=>1];
$del =  $article->delete($where);
if($del){
    echo '删除成功！';
}else{
    echo '删除失败！';
}
// 获取符合条件的记录数
$where = ['author'=>'tanking'];
$count = $article->getcount($where);
echo $count;
// 执行原生sql语句
$sql = 'select * from article where id=3';
$lists = $article->findsql($sql);
print_r($lists);
// 根据条件查询出对应的字段的值
$where = ['id'=>1];
$res = $article->getfield($where,'title');
if ($res) {
    echo $res;
}else{
    echo "没有数据";
}
// 高级查询
// $conditions查询条件
// $order排序方法
// $fields指定字段
// $limit查询条数
$res = $article->findall($conditions=null,$order='id asc',$fields=null,$limit=null);
if ($res) {
    print_r($res);
}else{
    print_r("没有数据");
}