YII2框架中操作数据库的方式实例分析

 // YII2中通过createCommand来处理数据库 // 查询多条记录 // {{%user}} 表示如果设置了表前缀，YII会自动帮你替换 $data1 = YII::$app->db->createCommand('select * from {{%user}}')->queryAll(); // 查询一条记录 // createCommand的第二个参数可以进行参数绑定 $data2 = YII::$app->db->createCommand('select * from {{%user}} where id=:id', ['id' => 2])->queryOne(); // 返回一列(第一列)数据 $data3 = YII::$app->db->createCommand('select name from {{%user}}')->queryColumn(); // 返回一个标量值，常用于统计 $data4 = YII::$app->db->createCommand('select count(*) as cnt from {{%user}}')->queryScalar(); // 绑定参数，防止SQL注入问题 // bindValue绑定一个参数 $data5 = YII::$app->db->createCommand('select * from {{%user}} where id=:id') ->bindValue(':id', 3) ->queryOne(); // 绑定多个参数 $data6 = YII::$app->db->createCommand('select * from {{%user}} where id=:id and name=:name') ->bindValues([':id' => 5, ':name' => 'eee']) ->queryOne(); // 绑定参数引用 $id = 7; $data7 = YII::$app->db->createCommand('select * from {{%user}} where id=:id') ->bindParam(':id', $id) ->queryOne(); // 执行非查询语句 $data8 = YII::$app->db->createCommand('update {{%user}} set name=:name where id=:id') ->bindValues([':name' => 'abcdef', ':id' => 8]) ->execute(); // 当然，我们也可以用更加简便的方法 // insert()插入 $data9 = YII::$app->db->createCommand()->insert('{{%user}}', [ 'name' => 'test', 'sex' => 1, 'age' => 28, ])->execute(); // batchInsert()批量插入 $data10 = YII::$app->db->createComma<strong style="color:transparent">来源gaodai#ma#com搞@@代~&码网</strong>nd()->batchInsert('{{%user}}', ['name', 'sex', 'age'], [ ['111', 1, 11], ['222', 1, 22], ])->execute(); // update()更新 $data11 = YII::$app->db->createCommand()->update('{{%user}}', [ 'name' => '1242143214' ], 'id=:id', ['id' => 10])->execute(); // delete()删除 $data12 = YII::$app->db->createCommand()->delete('{{%user}}', 'id=:id', ['id' => 11])->execute(); // 执行事务 $trans = YII::$app->db->beginTransaction(); try { YII::$app->db->createCommand()->update('{{%user}}', ['age' => 12], 'id=:id', ['id' => 13])->execute(); YII::$app->db->createCommand()->update('{{%user}}', ['age' => 22], 'id=:id', ['id' => 14])->execute(); $trans->commit(); } catch (\Exception $e) { //如果语句中有一个执行失败，那么就将回滚 $trans->rollBack(); throw $e; } // 获取表的定义信息 $info = YII::$app->db->getTableSchema('{{%user}}'); 

 <?php namespace app\models; use yii\db\ActiveRecord; class MyUser extends ActiveRecord { public static function tableName() { return '{{%user}}'; } } 

 // 查询一条记录 // asArray的作用是以数组形式返回结果 // find()会返回一个ActiveQuery对象，ActiveQuery对象继承自yii\db\Query，所以可以使用Query中的所有查询方法 $data1 = MyUser::find()->where(['id' => 1])->asArray()->one(); // 查询多条记录 $data2 = MyUser::find()->where([])->orderBy('id desc')->asArray()->all(); // 根据主键获取一条记录 $data3 = MyUser::findOne(3); // 根据主键获取多条记录 $data4 = MyUser::findAll([4, 5, 6, 7]); // 带条件查询多条记录 $data5 = MyUser::findAll(['sex' => 1]); // 运行原生SQL $data6 = MyUser::findBySql('select * from {{%user}} where id=:id', [':id' => 8])->asArray()->one(); // 添加数据 // 准备一个新的实例，然后设置对应字段属性，保存 $user = new MyUser(); $user->name = 'test'; $user->sex = 1; $user->age = 22; $user->save(); // 修改数据 // 先获取一个对象，然后设置对应字段属性，保存 $upd = MyUser::findOne(10); $upd->name = 'abcdefg'; $upd->save(); // 修改多条数据 $data7 = MyUser::updateAll(['name' => 'update'], ['sex' => 1]); // 删除一条数据 $del = MyUser::findOne(15); $del->delete(); // 删除多条数据 $data8 = MyUser::deleteAll(['sex' => 0]); // 事务操作 $user2 = MyUser::findOne(22); $user3 = MyUser::findOne(33); $trans = MyUser::getDb()->beginTransaction(); try { $user2->name = '2222'; $user3->name = '3333'; //修改数据 $user2->save(); $user3->save(); $trans->commit(); } catch (\Exception $e) { $trans->rollBack(); throw $e; }