增删改查类

<?php
// 所有数据表的基类
abstract class Model {
	protected $tableName = "";
	protected $pdo = "";
	protected $sql="";
	function __construct() {
		$pdo = new PDO( "mysql:host=" . DB_HOST . ";dbname=" . DB_NAME, DB_USERNAME, DB_PASSWORD );
		$pdo->exec ( "set names " . DB_CHARSET );
		$this->pdo = $pdo;
	}
	function updatetone($where=''){
		$sql = 'UPDATE ' . $this->tableName . ' SET clicknum=clicknum+1'. ($where == NULL ? $where : ' WHERE ' . $where);
		$this->sql=$sql;
		return $this->pdo->exec ( $sql );
	}
	/**
	 * 获取总记录数 select count(*) as num from news where cateid=5
	 */
	function count($where=""){
		$where = empty($where) ? "" : " where ".$where;
		$sql="select count(*) as num from {$this->tableName} $where";
		$this->sql=$sql;
		$pdoS=$this->pdo->query($sql);
		$arr=$pdoS->fetch(PDO::FETCH_ASSOC);
		return $arr['num'];
	}
	/**
	 * 增加
	 * array $arr=array('字段名'=>值,....) exp:array('username'=>'xiaowang','password'=>'123456')
	 */
	function insert($arr) {
		// 把数组转化成sql语句
		// sql语句是php向mysql，告诉她给我写一条记录进表
		// insert into 表名(字段列表) value(数据列表)
		// insert into adminuser(username,password) value('xiaowang','123456')
		$fiedList = "";
		$valueList = "";
		foreach ( $arr as $k => $v ) {
			$fiedList .= "," . $k;
			$valueList .= ",'" . $v . "'";
		}
		$fiedList = substr ( $fiedList, 1 );
		$valueList = substr ( $valueList, 1 );
		// 拼sql
		$sql = "insert into {$this->tableName}({$fiedList}) value({$valueList})";
		$this->sql=$sql;
		// 执行
		$re = $this->pdo->exec ( $sql );
		if ($re) {
			// 返回主键id
			return $this->pdo->lastInsertId ();
		} else {
			return false;
		}
	}
	// 查询
	function findByPk($id) {
		// 获取表的主键名称 desc 表名
		$pdoS = $this->pdo->query ( "desc " . $this->tableName );
		$arr = $pdoS->fetchAll ( PDO::FETCH_ASSOC );
		foreach ( $arr as $v ) {
			if ($v ['Key'] == 'PRI') {
				$fieldName = $v ['Field'];
				break;
			}
		}
		$sql = "select * from {$this->tableName} where $fieldName=$id";
		$this->sql=$sql;
		$pdoS = $this->pdo->query ( $sql );
		return $pdoS->fetch ( PDO::FETCH_ASSOC );
	}
	/**
	 * 查询多条记录
         * array $arr 用来管理查询语句的子句
	 * array('limit'=>'0,5','where'=>"id=5")
	 */
	function findAll($arr = array()) {
		// select 字段列表 from 表名
		// where 条件 group by 字段 having 条件 order by 字段 desc|asc limit start,length
		// select 字段列表 from 表1 as t1 join 表2 as t2 on t1.字段=t2.字段 join 表3 as t3 on t2.字段=t3.字段
		// 拼sql语句
		$field = isset ( $arr ['field'] ) ? $arr ['field'] : "*";
		$where = isset ( $arr ['where'] ) ? " where " . $arr ['where'] : '';
		$group = isset ( $arr ['group'] ) ? " group by " . $arr ['group'] : '';
		$having = isset ( $arr ['having'] ) ? " having " . $arr ['having'] : "";
		$order = isset ( $arr ['order'] ) ? " order by " . $arr ['order'] : '';
		$limit = isset ( $arr ['limit'] ) ? " limit " . $arr ['limit'] : '';
		$alias = isset ( $arr ['alias'] ) ? " as " . $arr ['alias'] : "";
		$join = isset ( $arr ['join'] ) ? " join " . $arr ['join'] : '';
		$sql = "select $field from {$this->tableName} $alias $join $where $group $having $order $limit";
		$this->sql=$sql;
		$pdoS = $this->pdo->query ( $sql );
		if (is_object ( $pdoS )) {
			return $pdoS->fetchAll ( PDO::FETCH_ASSOC );
		} else {
			return array ();
		}
	}
	function delete($where = NULL) {
		$sql = 'DELETE FROM ' . $this->tableName . ($where == NULL ? $where : ' WHERE ' . $where);
		$this->sql=$sql;
		return $this->pdo->exec ( $sql );
	}
	function update($bind, $where = NULL) {
		$set = NULL;
		foreach ( $bind as $field => $value ) {
			if (is_null ( $set )) {
				$set .= $field . "='" . $value . "'";
			} else {
				$set .= ',' . $field . "='" . $value . "'";
			}
		}
		$sql = 'UPDATE ' . $this->tableName . ' SET ' . $set . ($where == NULL ? $where : ' WHERE ' . $where);
		$this->sql=$sql;
		return $this->pdo->exec ( $sql );
	}
	function query($sql){
		//判断是更新语句，还是查询语句
		if(preg_match("/^select/i",$sql)){
			$pdoS=$this->pdo->query($sql);
			return $pdoS->fetchAll(PDO::FETCH_ASSOC);
		}else{
			return $this->pdo->exec($sql);
		}
	}
	function getLastSql(){
		return $this->sql;
	}
}