<?php$config = include 'config.php'; //引入数据库配置文件
$model = new Model($config);
//测试案例
// $saveData=['username'=>'张三','mobile'=>12334123];
// echo $model->table('user')->insert($saveData);
// var_dump($model->table('user')->where('id=5')->delete());
// var_dump($model->table('user')->limit('0,6')->field('username,mobile')->where('id>1')->order('id desc')->select());
// $updateData=['username'=>'张三'];
// var_dump($model->table('user')->where('id=3')->update($updateData));
// var_dump($model->table('user')->max('mobile'));
// var_dump($model->table('user')->getByUserName('张三'));
// var_dump($model->sql);class Model
{//主机名protected $host;//用户名protected $user;//密码protected $pwd;//数据库名protected $dbname;//字符集protected $charset;//数据库前缀protected $prefix;//数据库连接资源protected $link;//数据表名       这里可以自己指定表名protected $tableName;//sql语句protected $sql;//操作数组   存放的就是所有的查询条件protected $options;/*** 构造方法，对成员变量进行初始化** @param [type] $config*/function __construct($config){//对成员变量一一进行初始化$this->host = $config['DB_HOST'];$this->user = $config['DB_USER'];$this->pwd = $config['DB_PWD'];$this->dbname = $config['DB_NAME'];$this->charset = $config['DB_CHARSET'];$this->prefix = $config['DB_PREFIX'];//连接数据库$this->link = $this->connect();//得到数据表名  user===>UserModel$this->tableName = $this->getTableName();//初始化option数组$this->initOptions();}/*** 连接数据库** @return void*/protected function connect(){$link = mysqli_connect($this->host, $this->user, $this->pwd);if (!$link) {die('数据库连接失败');}//选择数据库mysqli_select_db($link, $this->dbname);//设置字符集mysqli_set_charset($link, $this->charset);//返回连接成功的资源return $link;}/*** 得到数据表名** @return void*/protected function getTableName(){//第一种，如果设置了成员变量，那么通过成员变量来得到表名if (!empty($this->tableName)) {return $this->prefix . $this->tableName;}//第二种，如果没有设置成员变量，那么通过类名来得到表名//得到当前类名字符串$className = get_class($this);//user  UserModel   goods  GoodsModel$table = strtolower(substr($className, 0, -5));return $this->prefix . $table;}/*** 初始化option数组** @return void*/protected function initOptions(){$arr = ['where', 'table', 'field', 'order', 'group', 'having', 'limit'];foreach ($arr as $value) {//将options数组中这些键对应的值全部清空$this->options[$value] = '';if ($value === 'table') {$this->options[$value] = $this->tableName;} elseif ($value == 'field') {$this->options[$value] = '*';}}}/*** field方法** @param [type] $field* @return void*/function field($field){//如果不为空，再进行处理if (!empty($field)) {if (is_string($field)) {$this->options['field'] = $field;} elseif (is_array($field)) {$this->options['field'] = join(',', $field);}}return $this;}/*** //table方法** @param [type] $table* @return void*/function table($table){if (!empty($table)) {$this->options['table'] = $this->prefix . $table;}return $this;}/*** where方法** @param [type] $where* @return void*/function where($where){if (!empty($where)) {$this->options['where'] = 'where ' . $where;}return $this;}/*** group方法** @param [type] $group* @return void*/function group($group){if (!empty($group)) {$this->options['group'] = 'group by ' . $group;}return $this;}/*** having方法** @param [type] $having* @return void*/function having($having){if (!empty($having)) {$this->options['having'] = 'having ' . $having;}return $this;}/*** order方法** @param [type] $order* @return void*/function order($order){if (!empty($order)) {$this->options['order'] = 'order by ' . $order;}return $this;}/*** limit方法** @param [type] $limit* @return void*/function limit($limit){if (!empty($limit)) {if (is_string($limit)) {$this->options['limit'] = 'limit ' . $limit;} elseif (is_array($limit)) {$this->options['limit'] = 'limit ' . join(',', $limit);}}return $this;}/*** select方法** @return void*/function select(){//先预写一个带占位符的sql语句$sql = 'select %FIELD% from %TABLE% %WHERE% %GROUP% %HAVING% %ORDER% %LIMIT%';//将options中对应的值依次的替换上面的占位符$sql = str_replace(['%FIELD%', '%TABLE%', '%WHERE%', '%GROUP%', '%HAVING%', '%ORDER%', '%LIMIT%'],[$this->options['field'], $this->options['table'], $this->options['where'], $this->options['group'],$this->options['having'], $this->options['order'], $this->options['limit']],$sql);//保存一份sql语句$this->sql = $sql;//执行sql语句return $this->query($sql);}/*** query** @param [type] $sql* @return void*/function query($sql){//清空option数组中的值$this->initOptions();//执行sql语句$result = mysqli_query($this->link, $sql);//提取结果集存放到数组中if ($result && mysqli_affected_rows($this->link)) {while ($data = mysqli_fetch_assoc($result)) {$newData[] = $data;}}//返回结果集return $newData;}/*** exec** @param [type] $sql* @param boolean $isInsert* @return void*/function exec($sql, $isInsert = false){//清空option数组中的值$this->initOptions();//执行sql语句$result = mysqli_query($this->link, $sql);if ($result && mysqli_affected_rows($this->link)) {//判断是否是插入语句，根据不同的语句返回不同的结果if ($isInsert) {return mysqli_insert_id($this->link);} else {return mysqli_affected_rows($this->link);}}return false;}function __get($name){if ($name == 'sql') {return $this->sql;}return false;}/*** insert函数* insert into 表名(字段) value(值)** @param [type] $data  关联数组，键就是字段名，值是字段值* @return void*/function insert($data){//处理值是字符串问题，两边需要添加单或双引号$data = $this->parseValue($data);//提取所有的键，即就是所有的字段$keys = array_keys($data);//提取所有的值$values = array_values($data);//增加数据的sql语句$sql = 'insert into %TABLE%(%FIELD%) values(%VALUES%)';$sql = str_replace(['%TABLE%', '%FIELD%', '%VALUES%'], [$this->options['table'], join(',', $keys), join(',', $values)], $sql);$this->sql = $sql;return $this->exec($sql, true);}/*** 传递进来一个数组，将数组中值为字符串的两边加上引号** @param [type] $data* @return void*/protected function parseValue($data){//遍历数组，判断是否为字符串，若是字符串，将其两边添加引号foreach ($data as $key => $value) {if (is_string($value)) {$value = '"' . $value . '"';}$newData[$key] = $value;}//返回处理后的数组return $newData;}/*** 删除函数** @return void*/function delete(){//拼接sql语句$sql = 'delete from %TABLE% %WHERE%';$sql = str_replace(['%TABLE%', '%WHERE%'], [$this->options['table'], $this->options['where']], $sql);//保存sql语句$this->sql = $sql;//执行sql语句return $this->exec($sql);}/*** 更新函数* update 表名 set 字段名=字段值，字段名=字段值 where** @param [type] $data* @return void*/function update($data){//处理$data数组中值为字符串加引号的问题$data = $this->parseValue($data);//将关联数组拼接为固定的格式  键=值，键=值$value = $this->parseUpdate($data);//准备sql语句$sql = 'update %TABLE% set %VALUE% %WHERE%';$sql = str_replace(['%TABLE%', '%VALUE%', '%WHERE%'], [$this->options['table'], $value, $this->options['where']], $sql);//保存sql语句$this->sql = $sql;//执行sql语句return $this->exec($sql);}/*** 将关联数组拼接为固定的格式** @param [type] $data* @return void*/protected function parseUpdate($data){foreach ($data as $key => $value) {$newData[] = $key . '=' . $value;}return join(',', $newData);}/*** max函数** @param [type] $field* @return void*/function max($field){//通过调用自己封装的方法进行查询$result = $this->field('max(' . $field . ') as max')->select();//select方法返回的是一个二维数组return $result[0]['max'];}/*** 析构方法*/function __destruct(){mysqli_close($this->link);}/*** getByName   getByAge** @param [type] $name* @param [type] $args* @return void*/function __call($name, $args){//获取前5个字符$str = substr($name, 0, 5);//获取后面的字段名$field = strtolower(substr($name, 5));//判断前五个字符是否是getbyif ($str === 'getBy') {return $this->where($field . '="' . $args[0] . '"')->select();}return false;}
}

<?php
return ['DB_HOST'=>'localhost','DB_USER'=>'root','DB_PWD'=>'123456','DB_NAME'=>'test','DB_CHARSET'=>'utf8','DB_PREFIX'=>'t_',
];