?php
namespace app\index\controller;
use think\Controller;
use think\Db;
class Index extends Controller
{
  public function study_db(){
    //方式一：默認(rèn)讀取配置文件的配置
    $res = Db::connect();
    //方式二：手動(dòng)配置，使用一個(gè)數(shù)組
    $res = Db::connect([
      'type'      => 'mysql',
      'hostname'    => '127.0.0.1',
      'database'    => 'bodywork3',
      'username'    => 'root',
      'password'    => '666',
      'hostport'    => '3306',
      'charset'     => 'utf8'
    ]);
    //方式三：手動(dòng)配置，使用一個(gè)字符串
    $res = Db::connect("mysql://root:password@127.0.0.1:3306/database_name#utf8");
    //方式四：手動(dòng)配置，使用一個(gè)字符串
    //這種方式，需要在config配置文件中有tp_db_config數(shù)組配置
   $res = Db::connect("tp_db_config");
  }
}

    $data = Db::query("select * from user");
    dump($data);
 　　  $data = Db::table('user')->select();
 　　  $data = Db::table('user')->find();
　　  //獲取一條記錄的某個(gè)字段值
    $name = Db::table('user')->where(['id']=>5)->value('name');
    //獲取一列值
    $all_name = Db::table('user')->column('name');
    //獲取一列值，第二個(gè)參數(shù)作為索引
    $all_name = Db::table('user')->column('name','id');
    //注意：
    //select和column獲取不到數(shù)據(jù)時(shí)返回空數(shù)組。 
    //find和value獲取不到數(shù)據(jù)時(shí)返回null。
    $data = db('user')->select();//每次會(huì)實(shí)例化類
    $data = db('user',[],false)->select();//每次不會(huì)實(shí)例化類

//表名字，使用table    
$data = Db::table('prefix_user')->select();
//表名字，使用name
$data = Db::name('user')->select();  
//使用table()時(shí)需要帶上表前綴，
//使用name()時(shí)不需要表前綴，

//執(zhí)行sql語句添加數(shù)據(jù)
Db::execute("insert into user values (1,'name',10)");
//,返回影響的行數(shù)
$res = Db::name('user')->insert([
  'name' => 'hello',
  'age' => 10
]);
//insertGetId()方法可以在添加數(shù)據(jù)后返回?cái)?shù)據(jù)的id
$id = Db::name('user')->insertGetId([
  'name' => 'hello',
  'age' => 10
]);
//添加多個(gè)數(shù)據(jù),返回影響的行數(shù)
$res= Db::name('user')->insertAll([
  ['name' => 'hello','age' => 10],
  ['name' => 'world','age' => 12],
]);

    //更新多個(gè)字段
    $res = Db::name('user')-where(['id'=>1])->update([
      'username' => 'zhang san',
      'age' => '6'
    ]);
    //更新一個(gè)字段
    $res = Db::name('user')-where(['id'=>1])->setField('username','zhang san');
    //自增、自減
    $res = Db::name('user')-where(['id'=>1])->setInc('score');
    $res = Db::name('user')-where(['id'=>1])->setDec('score');
    $res = Db::name('user')-where(['id'=>1])->setInc('score',2);

//刪除一條記錄
$res = Db::name('user')->where(['id'=>1])->delete();
//如果where條件是主鍵，可以這樣寫
$res = Db::name('user')->delete(1);

    //打印sql,where值為數(shù)組
    $sql = Db::name('user')->where(['id'=>1])->buildSql();
    dump($sql);
    //結(jié)果：SELECT * FROM `user` WHERE `id` = 1
    //打印sql,where值為兩個(gè)參數(shù)
    $sql2 = Db::name('user')->where('id',1)->buildSql();
    dump($sql2);
    //結(jié)果：SELECT * FROM `user` WHERE `id` = 1
    //打印sql,where值為三個(gè)參數(shù)
    $sql3 = Db::name('user')->where('id','=',1)->buildSql();
    dump($sql3);
    //結(jié)果：SELECT * FROM `user` WHERE `id` = 1
    //打印sql,where多條件
    $sql4 = Db::name('user')->where([
      'id' => ['in',[1,2,3,4,5]],
      'age' => ['gt',10]
    ])->buildSql();
    dump($sql4);
    //結(jié)果：SELECT * FROM `user` WHERE `id` IN (1,2,3,4,5) AND `age` > 10
    //使用EXP表達(dá)式
    $sql5 = Db::name('user')->where('id','EXP','not in (2,5)')->buildSql();
    dump($sql5);
    //結(jié)果：SELECT * FROM `bw_user` WHERE ( `id` not in (2,5) )
    //可以使用連續(xù)的where條件
    $sql6 = Db::name('user')
      ->where('id','EXP','not in (2,5)')
      ->where('age','>',10)
      ->buildSql();
    dump($sql6);
    //結(jié)果：SELECT * FROM `bw_user` WHERE ( `id` not in (2,5) ) AND `age` > 10
    //如果多個(gè)where條件是or關(guān)系，使用whereOr
    $sql7 = Db::name('user')
      ->where('id','EXP','not in (2,5)')
      ->whereOr('age','>',10)
      ->buildSql();
    dump($sql7);
    //結(jié)果：SELECT * FROM `bw_user` WHERE ( `id` not in (2,5) ) OR `age` > 10