PHP教程之数据库操作类封装

<?php

/**
 * 1、连贯操作
 * 返回$this
 * 2、字符串替换
 * str_replace
 */
$database = include('config/database.php');

$model = new Model();
$result = $model->getBy('id',30);

/*
$result = $model->getByUsername('xiaoming'); 
//作业：
1、实现getByXxx系列函数
2、实现聚合函数(count、max、min、avg、sum)
$result = $model->table('user,aaa')->select(MYSQLI_ASSOC);

if ($_SERVER['REMOTE_ADDR'] == '::1') {
$ip = ip2long('127.0.0.1');
} else {
$ip = ip2long($_SERVER['REMOTE_ADDR']);
}
$data = ['username'=>'xiaohang','password'=>md5('123456'),'regip'=>$ip,'aaaa'=>'bbb'];
$result = $model->insert($data,true);

$result = $model->where('id=94')->delete();

$result = $model->where('id=93')->update(['username'=>'xiaosun']);
*/
var_dump($result);
echo $model->getLastSql();

class Model
{
//数据库连接
protected $link;
//主机地址
protected $host;
//用户名
protected $user;
//密码
protected $pwd;
//数据库名
protected $dbName;
//数据表名
protected $tableName = 'user';
//字符集
protected $charset;
//表前缀
protected $prefix;
//缓存字段
protected $fields;
//缓存目录
protected $cache;
//保存所有的参数
protected $options;
//保存最后执行的SQL语句
protected $sql;

public function __construct($config=null)
{
if (empty($config)) {
if (empty($GLOBALS['database'])) {
$config = include('config/database.php');
} else {
$config = $GLOBALS['database'];
}
}
$this->host = $config['DB_HOST']; 
$this->user = $config['DB_USER'];
$this->pwd = $config['DB_PWD'];
$this->dbName = $config['DB_NAME'];
$this->prefix = $config['DB_PREFIX'];
$this->charset = $config['DB_CHARSET'];
$this->cache = $this->checkCache($config['DB_CACHE']);
if (!($this->link = $this->connect())) {
exit('数据库连接失败');
}
$this->tableName = $this->getTableName();
$this->fields = $this->getFields();
$this->options = $this->initOptions();
}

protected function connect()
{
$link = mysqli_connect($this->host,$this->user,$this->pwd);
if (!$link) {
return false;
}
if (!mysqli_select_db($link,$this->dbName)) {
mysqli_close($link);
return false;
}
if (!mysqli_set_charset($link,$this->charset)) {
mysqli_close($link);
return false;
}
return $link;
}

public function where($where)
{
if (is_string($where)) {
$this->options['where'] = 'where ' . $where;
} else if (is_array($where)) {
$this->options['where'] = 'where ' . join(' and ',$where);
}
return $this;
}

public function group($group)
{
if (is_string($group)) {
$this->options['group'] = 'group by ' . $group;
} else if (is_array($group)) {
$this->options['group'] = 'group by ' . join(',',$group);
}
 return
$this;
}

public function order($order)
{
if (is_string($order)) {
$this->options['order'] = 'order by ' . $order;
} else if (is_array($order)) {
$this->options['order'] = 'order by ' . join(',',$order);
}
 return
$this;
}

public function having($having)
{
if (is_string($having)) {
$this->options['having'] = 'having ' . $having;
} else if (is_array($having)) {
$this->options['having'] = 'having ' . join(' and ',$having);
}
 return
$this;
}

public function limit($limit)
{
if (is_string($limit)) {
$this->options['limit'] = 'limit ' . $limit;
} else if (is_array($limit)) {
$this->options['limit'] = 'limit ' . join(',',$limit);
}
 return
$this;
}

public function table($table)
{
if (is_string($table)) {
$table = explode(',', $table);
} 
if (is_array($table)) {
foreach ($table as $key => $value) {
$value = ltrim($value,$this->prefix);
$table[$key] = $this->prefix . $value;
}
$this->options['table'] = join(',',$table);
}
return $this;
}

public function fields($fields)
{
if (is_string($fields)) {
$this->options['fields'] = $fields;
} else if (is_array($fields)) {
$this->options['fields'] = join(',',$fields);
}
 return
$this;
}

public function insert($data,$insertId=false)
{
//必须是数组
if (!is_array($data)) {
return '插入时传递的参数必须是数组';
}
$data = $this->checkInsert($data);
$this->options['fields'] = join(',',array_keys($data));
$this->options['values'] = join(',',$data);

$sql = 'INSERT INTO %TABLE%(%FIELDS%) VALUES(%VALUES%)';
$sql = str_replace(
[
'%FIELDS%',
'%TABLE%',
'%VALUES%', 
], 
[
$this->options['fields'],
$this->options['table'],
$this->options['values'],
], 
$sql
);
return $this->exec($sql,$insertId);
}

public function delete()
{
if (empty($this->options['where'])) {
return '删除数据时请务必写上条件';
}
$sql = 'DELETE FROM %TABLE% %WHERE% %ORDER% %LIMIT%';
$sql = str_replace(
[
'%TABLE%',
'%WHERE%',
'%ORDER%', 
'%LIMIT%', 
], 
[
$this->options['table'],
$this->options['where'],
$this->options['order'],
$this->options['limit'],
], 
$sql
);
return $this->exec($sql);
}

public function update($data)
{
if (empty($this->options['where'])) {
return '更新数据时请务必写上条件';
}
if (!is_array($data)) {
return '必须传递数组';
}
$data = $this->checkUpdate($data);
$this->options['set'] = $data;
$sql = 'UPDATE %TABLE% SET %SET% %WHERE% %ORDER% %LIMIT%';
$sql = str_replace(
[
'%TABLE%',
'%SET%',
'%WHERE%',
'%ORDER%', 
'%LIMIT%', 
], 
[
$this->options['table'],
$this->options['set'],
$this->options['where'],
$this->options['order'],
$this->options['limit'],
], 
$sql
);
return $this->exec($sql);
}

public function select($resultType = MYSQLI_BOTH)
{
$sql = 'SELECT %FIELDS% FROM %TABLE% %WHERE% %ORDER% %GROUP% %HAVING% %LIMIT%';
$sql = str_replace(
[
'%FIELDS%',
'%TABLE%',
'%WHERE%', 
'%ORDER%',
'%GROUP%',
'%HAVING%',
'%LIMIT%',
], 
[
$this->options['fields'],
$this->options['table'],
$this->options['where'],
$this->options['order'],
$this->options['group'],
$this->options['having'],
$this->options['limit'],
], 
$sql
);
return $this->query($sql,$resultType);
}

public function getLastSql()
{
return $this->sql;
}

protected function exec($sql,$insertId=false)
{
//保存SQL语句
$this->sql = $sql;
//每次执行完SQL语句都要初始化条件
$this->options = $this->initOptions();

$result = mysqli_query($this->link,$sql);
if ($result && $insertId) {
return mysqli_insert_id($this->link);
}
return $result;
}

protected function query($sql,$resultType = MYSQLI_BOTH)
{
//保存SQL语句
$this->sql = $sql;
//每次执行完SQL语句都要初始化条件
$this->options = $this->initOptions();

$result = mysqli_query($this->link,$sql);
if ($result) {
return mysqli_fetch_all($result,$resultType);
}
return $result;
}

protected function addQuotes($data)
{
if (is_array($data)) {
foreach ($data as $key => $value) {
if (is_string($value)) {
$data[$key] = '\'' . $value . '\'';
}
}
}
return $data;
}

protected function initOptions()
{
$fields = join(',',array_unique($this->fields));
return [
'where' =>'',
'order' =>'',
'group' =>'',
'having' =>'',
'limit' =>'',
'fields' =>$fields,
'table' =>$this->tableName,
];
}

protected function getFields()
{
//拼接缓存文件路径名
$cacheFile = $this->cache . $this->tableName . '.php';
if (file_exists($cacheFile)) {
return include($cacheFile);
}
//不存在需要进行缓存处理
$sql = 'desc ' . $this->tableName;
$result = $this->query($sql, MYSQLI_ASSOC);
$fields = [];
foreach ($result as $key => $value) {
if ($value['Key'] == 'PRI') {
$fields['_pk'] = $value['Field'];
}
$fields[] = $value['Field'];
}
$data = "<?php \n return " . var_export($fields,true) . ';';
file_put_contents($cacheFile,$data);
return $fields;
}

protected function getTableName()
{
if ($this->tableName) {
return $this->prefix . $this->tableName;
}
//\index\model\User
$className = get_class($this);
if ($pos = strrpos($className,'\\')) {
$className = strtolower(substr($className, $pos+1));
}
return $this->prefix . $className;
 }

 protected
function checkCache($dir)
 {
 $dir
= rtrim($dir,'/') . '/';
 if
(!is_dir($dir)) {
 mkdir($dir,0777,true);
 }
 if
(!is_readable($dir) || !is_writable($dir)) {
 chmod($dir,
0777);
 }
 return
$dir;
 }

 protected
function checkInsert($data) 
 {
 $fields
= array_flip($this->fields);
 $data
= array_intersect_key($data,$fields);
 $data
= $this->addQuotes($data);
 return
$data;
 }

 protected
function checkUpdate($data)
 {
 $fields
= array_flip($this->fields);
 $data
= array_intersect_key($data,$fields);
 $data
= $this->addQuotes($data);
 $realData
= '';
 foreach
($data as $key => $value) {
 $realData
.= $key . '=' . $value . ',';
 }
 return
substr($realData,0,-1); 
 }

 public
function getBy($field,$value)
 {
 //将驼峰转换为下划线
RegTime => reg_time
 $realField
= strtolower($field[0]);
 $len
= strlen($field);
 for
($i=1; $i < $len; $i++) { 
 $lower
= strtolower($field[$i]);
 if
($lower != $field[$i]) {
 $realField
.= '_';
 }
 $realField
.= $lower;
 }
 if
(is_string($value)) {
 $value
= '\'' . $value . '\'';
 }
 $where
= $realField . '=' .$value;
 return
$this->where($where)->select();
 }

}

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