一、数据库的链接方式

namespace app\index\controller;

use think\Db;

class Demo

{

//1、全局配置 config/database.php配置

public function dbTest()

{

return Db::table('pzq_article')

->where('id','29')

->value('title');

}

//2、动态配置 think\db\Query.php中有一个方法connect()

public function dbTest2()

{

return Db::connect([

'type'=>'mysql',

'hostname'=>'localhost',

'database'=>'top789',

'username'=>'root',

'password'=>'root',

])

->table('pzq_article')

->where('id','76')

->value('title');

}

//3、DSN连接

public function dbTest3()

{

$dsn = 'mysql://root:root@localhost:3306/top789#utf8';

return Db::connect($dsn)

->table('pzq_article')

->where('id','88')

->value('title');

}

//4、单条查旬

public function dbTest4()

{

$res = Db::table('pzq_article')

->field(['title'=>'标题','id'=>'编号'])//可添加别名

->where('id','=',20)//如果是等号，=可以省略

->find();//如果是主键查询，可省略上面where,这行写->find(20);

dump(is_null($res)?'没有查到':$res);

}

//5、多条查旬

public function dbTest5()

{

$res = Db::table('pzq_article')

->field(['id','cat_id','title'])

->where([

['id','>',20],

['cat_id','=',2],

])//一个条件，直接用表达式->where('id','>',20)。多个条件用数组

->order('id desc')->limit(3)->select();

if(empty($res)){

return '没有查到';

}else{

dump($res);

}

}

//6、数据添加

public function dbTest6()

{

$data = [

'name'=>'Sam2',

'age'=>'29',

'posttime'=>time()

];

$dataall=[

['name'=>'Sam3','age'=>'29','posttime'=>time()],

['name'=>'Sam4','age'=>'30','posttime'=>time()],

];

//(1)单条插入

//return Db::table('test')->data($data)->insert();

//(2)插入同时返回新增主键id

//return Db::table('test')->insertGetId($data);

//(3)插入多条数据

return Db::table('test')->data($dataall)->insertAll();

}

//更新数据

public function dbTest7()

{

// return Db::table('test')

// ->where('id','=',4)

// ->update(['name'=>'SamC','age'=>'31']);

//如果where条件是主键，还可以如下使用

return Db::table('test')

->update(['name'=>'SamCheng','age'=>'30','id'=>4]);

}

//删除操作

public function dbTest8()

{

//return Db::table('test')->delete(6);

//或者

return Db::table('test')->where('id',5)->delete();

}

//mysql原生语句 查询

public function dbTest9()

{

$sql = "select name,age from test where id>2";

dump(Db::query($sql));

}

//mysql 增、删、改 用Db::execute($sql)

public function dbTest10()

{

//$sql = "update test set name='samC' where id=4";

//$sql = "insert test set name='Yan',age='30'";

$sql = "delete from test where id=4";

return Db::execute($sql);

}

}