YII2.0框架(四) 数据库操作yii\db\Commond

// 1. 执行SQL查询
 
            $admins = Yii::$app->db->createCommand('SELECT * FROM tb_admin')->queryAll(); //查询所有数据
 
询单条数据
 
//查询某列数据
             $admins = Yii::$app->db->createCommand('SELECT COUNT(id) FROM tb_admin WHERE id = 1')->queryScalar(); //查询标量
             // 2. 绑定参数
             $params = [':id' => 1];
             $id = 1;
             $admins = Yii::$app->db->createCommand('SELECT * FROM tb_admin WHERE id = :id')->bindValue(':id',1)->queryOne(); //查询单条数据
             $admins = Yii::$app->db->createCommand('SELECT * FROM tb_admin WHERE id = :id')->bindValues($params)->queryOne(); //查询单条数据
             $admins = Yii::$app->db->createCommand('SELECT * FROM tb_admin WHERE id = :id', $params)->queryOne(); //查询单条数据
             $admins = Yii::$app->db->createCommand('SELECT * FROM tb_admin WHERE id = :id')->bindParam(':id', $id)->queryOne(); //查询单条数据
             // 3. 执行非查询语句
             $rs = Yii::$app->db->createCommand('
                     UPDATE tb_admin SET name="小明" WHERE id=:id
                 ')->bindParam(':id', $id)->execute(); //修改单条数据
             $rs = Yii::$app->db->createCommand()->update('tb_admin', ['name'=>'小芳'], 'id=1')->execute(); //修改单条数据
             $rs = Yii::$app->db->createCommand()->insert('tb_admin', [
                 'name' => '小芳',
                 'phone' => '1500',
                 'role_id' => '10',
                 'password' => 'admin',
                 'created' => '2017-05-05 19:52:07',
                 ])->execute(); //插入单条数据
             $rs = Yii::$app->db->createCommand()->delete('tb_user', 'id=1')->execute(); //删除单条数据
             $rs = Yii::$app->db->createCommand()->batchInsert('tb_admin', ['name', 'phone', 'role_id', 'password', 'created'],[
                 ['小明','1233','23','23','2017-05-05 19:52:07'],
                 ['小明','1233','23','23','2017-05-05 19:52:07'],
                 ])->execute(); //插入多条数据
             // 4. 引用表和列名称 
             $admins = Yii::$app->db->createCommand('SELECT COUNT([[id]]) FROM {{tb_admin}} WHERE id = 1')->queryScalar(); //查询标量
             // 5. 使用表前缀 
             $admins = Yii::$app->db->createCommand('SELECT COUNT([[id]]) FROM {{%admin}} WHERE id = 1')->queryScalar(); //查询标量
             // 6. 执行事务
             Yii::$app->db->transaction(function($db){
                 $sql1 = 'UPDATE tb_admin SET name="小明" WHERE id=1';
                 $sql2 = 'UPDATE tb_user SET name="小明" WHERE id=12';
                 $db->createCommand($sql1)->execute();
                 $db->createCommand($sql2)->execute();
             });
             $db = Yii::$app->db;
             $transaction = $db->beginTransaction();
             try {
                 $sql1 = 'UPDATE tb_admin SET name="11明" WHERE id=1';
                 $sql2 = 'UPDATE tb_admin SET name="" WHERE id=null';
                 $db->createCommand($sql1)->execute();
                 $db->createCommand($sql2)->execute();
                 $transaction->commit();
             } catch (\Exception $e) {
                 $transaction->rollback();
                 throw $e;
             }