一个简易的ORM类

自己写的一个简易的ORM类，给感兴趣的朋友提供一点思路。
自己写的一个简易的ORM类，给感兴趣的朋友提供一点思路。借鉴了一点TP的思路。 /**
* author: NickBai
* createTime: 2016/11/28 0028 下午 4:00
*/
class MyOrm implements ArrayAccess
{
public $host = '127.0.0.1'; //数据库地址
public $dbname = 'test'; //数据库名
public $user = 'root'; //数据库用户名
public $pwd = 'root'; //数据库密码
public $port = '3306'; //数据库端口
public $charset = 'utf8'; //数据库编码
private $conn = null; //数据库链接资源
private $alias = []; //记录全局的语句参数
private $sql; //存储最后一条sql

public function __construct()
{
if( is_null( $this->conn ) ){

$dsn = "mysql:host=$this->host;dbname=$this->dbname;charset=$this->charset;port=$this->port";
$this->conn = new PDO( $dsn, $this->user, $this->pwd );
}
}

//field语句
public function field( $field )
{
if( !is_string( $field ) ){
throw new exception("field语句的参数必须为字符串");
}

$this->alias['field'] = $field;
return $this;
}

//table语句
public function table( $table )
{
if( !is_string( $table ) ){
throw new exception("table语句的参数必须为字符串");
}

$this->alias['table'] = $table;
return $this;
}

//where语句
public function where( $where )
{
$this->alias['where'] = '';
if( is_array( $where ) ){

foreach( $where as $key=>$vo ){
$this->alias['where'] .= " `$key`" . ' = ' . $vo . ' and ';
}
$this->alias['where'] = rtrim( $this->alias['where'], 'and ' );

}else if( is_string( $where ) ){

$this->alias['where'] = $where;
}else{

throw new exception("where语句的参数必须为数组或字符串");
}

return $this;
}

//limit语句
public function limit( $limit )
{
$this->alias['limit'] = '';
if( is_numeric( $limit ) ){
$this->alias['limit'] = '0,' . $limit;
}else if( is_string( $limit ) ){
$this->alias['limit'] = $limit;
}else{
throw new exception("limit语句的参数必须为数字或字符串");
}

return $this;
}

//order语句
public function order( $order )
{
if( !is_string( $order ) ){
throw new exception("order语句的参数必须为字符串");
}

$this->alias['order'] = $order;
return $this;
}

//group语句
public function group( $group )
{
if( !is_string( $group ) ){
throw new exception("group语句的参数必须为字符串");
}

$this->alias['group'] = $group;
return $this;
}

//解析查询sql语句
public function ParseSelectSql()
{
$this->sql = 'select *';
if( !empty( $this->alias['field'] ) ){
$this->sql = str_replace( '*', $this->alias['field'], $this->sql );
}

if( empty( $this->alias['table'] ) ){
throw new exception("请用table子句设置查询表");
}else{

$this->sql .= ' from ' . $this->alias['table'];
}

if( !empty( $this->alias['where'] ) ){
$this->sql .= ' where ' . $this->alias['where'];
}

if( !empty( $this->alias['group'] ) ){
$this->sql .= ' group by ' . $this->alias['group'];
}

if( !empty( $this->alias['order'] ) ){
$this->sql .= ' order by ' . $this->alias['order'];
}

if( !empty( $this->alias['limit'] ) ){
$this->sql .= ' limit ' . $this->alias['limit'];
}

}

//解析添加sql语句
public function ParseAddSql()
{
$this->sql = 'insert into ';
if( empty( $this->alias['table'] ) ){
throw new exception("请用table子句设置添加表");
}else{

$this->sql .= $this->alias['table'] . ' set ';
}

return $this->sql;
}

//解析更新sql语句
public function ParseUpdateSql()
{
$this->sql = 'update ';
if( empty( $this->alias['table'] ) ){
throw new exception("请用table子句设置修改表");
}else{

$this->sql .= $this->alias['table'] . ' set ';
}

if( empty( $this->alias['where'] ) ){
throw new exception("更新语句必须有where子句指定条件");
}

return $this->sql;
}

//解析删除sql语句
public function ParseDeleteSql()
{
$this->sql = 'delete from ';
if( empty( $this->alias['table'] ) ){
throw new exception("请用table子句设置删除表");
}else{

$this->sql .= $this->alias['table'];
}

if( empty( $this->alias['where'] ) ){
throw new exception("删除语句必须有where子句指定条件");
}

$this->sql .= ' where ' . $this->alias['where'];

return $this->sql;
}


//查询语句
public function select()
{
$this->ParseSelectSql();
$row = $this->conn->query( $this->sql )->fetchAll( PDO::FETCH_ASSOC );
$result = [];

foreach( $row as $key=>$vo ){

$arrObj = clone $this; //clone当前对象防止对this对象造成污染
$arrObj->data = $vo;
$result[$key] = $arrObj;
unset( $arrObj );
}

return $result;
}

//查询一条
public function find()
{
$this->ParseSelectSql();
$row = $this->conn->query( $this->sql )->fetch( PDO::FETCH_ASSOC );

$arrObj = clone $this; //clone当前对象防止对this对象造成污染
$arrObj->data = $row;
$result = $arrObj;
unset( $arrObj );

return $result;
}

//添加数据
public function add( $data )
{
if( !is_array( $data ) ){
throw new exception("添加数据add方法参数必须为数组");
}

$this->ParseAddSql();
foreach( $data as $key=>$vo ){
$this->sql .= " `{$key}` = '" . $vo . "',";
}

$this->conn->exec( rtrim( $this->sql, ',' ) );
return $this->conn->lastInsertId();
}

//更新语句
public function update( $data )
{
if( !is_array( $data ) ){
throw new exception("更新数据update方法参数必须为数组");
}

$this->ParseUpdateSql();
foreach( $data as $key=>$vo ){
$this->sql .= " `{$key}` = '" . $vo . "',";
}

$this->sql = rtrim( $this->sql, ',' ) . ' where ' . $this->alias['where'];
return $this->conn->exec( $this->sql );

}

//删除语句
public function delete()
{
$this->ParseDeleteSql();
return $this->conn->exec( $this->sql );
}

//获取查询数据
public function getData()
{
return $this->data;
}

//获取最后一次执行的sql语句
public function getLastSql()
{
return $this->sql;
}

public function __get($name)
{
return $this->getData()[$name];
}

public function offsetExists($offset)
{
if( !isset( $this->getData()[$offset] ) ){
return NULL;
}
}

public function offsetGet($offset)
{
return $this->getData()[$offset];
}

public function offsetSet($offset, $value)
{
return $this->data[$offset] = $value;
}

public function offsetUnset($offset)
{
unset( $this->data[$offset] );
}
}你可以这么用：$orm = new MyOrm();

//查询语句
$res = $orm->table('user')->order('id desc')->select();
$res = $orm->table('user')->where("name='test'")->order('id desc')->select();
$res = $orm->table('user')->where(['id' => 1])->order('id desc')->find();
$res = $orm->table('user')->where("age > 20")->group('group by name')->order('id desc')->limit(2)->select();
$res = $orm->table('user')->where("age > 20")->group('group by name')->order('id desc')->limit('2,2')->select();

//你可以这样处理数据
foreach( $res as $key=>$vo ){
echo $vo->name . '
';
}
//也可以这样处理
foreach( $res as $key=>$vo ){
echo $vo['name'] . '
';
}
//还可以这样
foreach( $res as $key=>$vo ){
print_r( $vo->getData() ) . '
';
}

//添加数据
$data = [
'name' => 'test1',
'age' => 20,
'password' => '21232f297a57a5a743894a0e4a801fc3',
'salt' => 'domain'
];
$res = $orm->table('user')->add( $data );

//更新数据
$res = $orm->table('user')->where(['id' => 4])->update( ['name' => 'sdfdsfdsd', 'salt' => '111'] );

//删除数据
$res = $orm->table('user')->where(['id' => 7, 'id' => 6])->delete();

//获取执行的sql语句
echo $orm->getLastSql();

var_dump($res);