YII 系列七Database

来源：互联网发布：windows android忘仙编辑：程序博客网时间：2024/06/06 21:30

>使用步骤

>>创建数据库

>>配置数据库连接

>>创建活动记录的模型

>>创建操作

>>创建渲染用的视图

>>运行

>foreach循环是PHP语句，在html语句中的穿插如下：

<span style="font-size:14px;"><?php foreach ($countries as $country): ?>    <li>        <?= Html::encode("{$country->name} ({$country->code})") ?>:        <?= $country->population ?>    </li><?php endforeach; ?></span>

//巧妙地解决了php中输出html语句需要使用html组成的字符串的问题

>&model= new user();与$query=User::find()生成的结果是不同的

前者是得到一个对象，可以通过调用属性和方法，进行操作；前者的道德是Activerecord

后者形成的是一个对象数组，本质是数组，可以调用数组的相关方法。后者得到的是Activequery

>数据库对象的使用activeForm

作用：it is the base class for classex representing relational data in terms of objects;

>>返回数据库和表的一些性质

activeAttributes()返回性质的名称在当前场景中

attributes() return the list of all attribute names of the model;

equals($record) returns a value indicatino whether the fiven active record is the same as the current one

primaryKey()返回主键名称，放在数组中

tabelName()返回表格的名称declares the name of the database table associated withe this AR class

>>delete系列

delete() the table row corresponding to this active record; attention:veforeDelete();afertDelete()

deleteall($condition='',$params=[]) delete rows in the table usein the provided conditions,参数使用where中的参数

deleteInternal() deletes an ActiveRecord without considering transction.

>>find系列：

find() creates an activequery instance fro query prupose.能够调用yii\db\activequery和yii\db\active\queryinterface中的方法，进行限定

findByCondition($condition,$one) finds ActiveRecord instances by the geiven condition.

findAll() returns a list of active record models that match the specified primary key values or a set of column valust;参数可以是a scalar value/an array scalar values/an array of name-value pairs.

findOne()returns a single(the first to be queryed) active record model instance by a primary key or an array of column values

findBySql($aql,$params=[ ])使用sql语句进行查询，其中$sql是sql字符串

>>get系列

getDb returns the database connerction used by thiis AR class.

getTableSchema() returns the schema infrormation of the DV tavle associated with AR class

>>insert系列

insert($runValidation= true,$attributes =null) inserts a row into the associated database table usering the attribute values of this record.

insertInternal() inserts an Active Recored into DB without considering transaction.

updata系列

update($runvalidation =true,$attributeNames = null)

updateAll(['status'=>1],'status=2')updates the whole table using the provided attribute values and conditions

updateAllConters() updates the whole table using the provided counter changes and conditioons.

>get到一个新的覆盖原函数的方法

<span style="font-size:14px;">class Customer extends ActiveRecord{    public static function find()    {        return parent::find()->where(['deleted' => false]);    }}// Use andWhere()/orWhere() to apply the default condition// SELECT FROM customer WHERE `deleted`=:deleted AND age>30$customers = Customer::find()->andWhere('age>30')->all();// Use where() to ignore the default condition// SELECT FROM customer WHERE age>30$customers = Customer::find()->where('age>30')->all();</span>

//使用parent调用覆盖之前的函数，有点意思

>yii\helpers\html（补充上一节中类的常用属性）