yii2.0框架是PHP开发的一个比较高效率的框架,集合了作者的大量心血,下面通过用户为例给大家详解yii2使用中的一些基本的增删改查操作。
User::find()->all(); //返回所有用户数据;
User::findOne($id); //返回 主键 id=1 的一条数据;
User::find()->where(['name' => 'ttt'])->one(); //返回 ['name' => 'ttt'] 的一条数据;
User::find()->where(['name' => 'ttt'])->all(); //返回 ['name' => 'ttt'] 的所有数据;
User::findBySql('SELECT * FROM user')->all(); //用 sql 语句查询 user 表里面的所有数据;
User::findBySql('SELECT * FROM user')->one(); 此方法是用 sql 语句查询 user 表里面的一条数据;
User::find()->andWhere(['sex' => '女', 'age' => '18'])->count('id'); //统计符合条件的总条数;
User::find()->one(); //返回一条数据;
User::find()->all(); //返回所有数据;
User::find()->count(); //返回记录的数量;
User::find()->average(); //返回指定列的平均值;
User::find()->min(); //返回指定列的最小值 ;
User::find()->max(); //返回指定列的最大值 ;
User::find()->scalar(); //返回值的第一行第一列的查询结果;
User::find()->column(); //返回查询结果中的第一列的值;
User::find()->exists(); //返回一个值指示是否包含查询结果的数据行;
yii2的group查询,以用户为例:
User::find()->addGroupBy('title')->all();根据title进行分组
1、增加 (insert)
$model = new User();
$model->username = '小伙儿';
$model->insert();
对数据库 删除的一些简单的操作,还是老样子,上面我写代码,如果样式混乱,我会附上截图。还是用 user 表为例
User::deleteAll('name = 小伙儿'); 删除 name = 小伙儿 的数据;
User::findOne($id)->delete(); 删除主键为 $id变量 值的数据库;
User::deleteAll('age > :age AND sex = :sex', [':age' => '20', ':sex' => '1']); 删除符合条件的数据;
推荐阅读:从零开始学YII2框架(一)通过Composer安装Yii2框架,相信对大家学习yii2会有所帮助的。

PHP type prompts to improve code quality and readability. 1) Scalar type tips: Since PHP7.0, basic data types are allowed to be specified in function parameters, such as int, float, etc. 2) Return type prompt: Ensure the consistency of the function return value type. 3) Union type prompt: Since PHP8.0, multiple types are allowed to be specified in function parameters or return values. 4) Nullable type prompt: Allows to include null values and handle functions that may return null values.

In PHP, use the clone keyword to create a copy of the object and customize the cloning behavior through the \_\_clone magic method. 1. Use the clone keyword to make a shallow copy, cloning the object's properties but not the object's properties. 2. The \_\_clone method can deeply copy nested objects to avoid shallow copying problems. 3. Pay attention to avoid circular references and performance problems in cloning, and optimize cloning operations to improve efficiency.

PHP is suitable for web development and content management systems, and Python is suitable for data science, machine learning and automation scripts. 1.PHP performs well in building fast and scalable websites and applications and is commonly used in CMS such as WordPress. 2. Python has performed outstandingly in the fields of data science and machine learning, with rich libraries such as NumPy and TensorFlow.

Key players in HTTP cache headers include Cache-Control, ETag, and Last-Modified. 1.Cache-Control is used to control caching policies. Example: Cache-Control:max-age=3600,public. 2. ETag verifies resource changes through unique identifiers, example: ETag: "686897696a7c876b7e". 3.Last-Modified indicates the resource's last modification time, example: Last-Modified:Wed,21Oct201507:28:00GMT.

In PHP, password_hash and password_verify functions should be used to implement secure password hashing, and MD5 or SHA1 should not be used. 1) password_hash generates a hash containing salt values to enhance security. 2) Password_verify verify password and ensure security by comparing hash values. 3) MD5 and SHA1 are vulnerable and lack salt values, and are not suitable for modern password security.

PHP is a server-side scripting language used for dynamic web development and server-side applications. 1.PHP is an interpreted language that does not require compilation and is suitable for rapid development. 2. PHP code is embedded in HTML, making it easy to develop web pages. 3. PHP processes server-side logic, generates HTML output, and supports user interaction and data processing. 4. PHP can interact with the database, process form submission, and execute server-side tasks.

PHP has shaped the network over the past few decades and will continue to play an important role in web development. 1) PHP originated in 1994 and has become the first choice for developers due to its ease of use and seamless integration with MySQL. 2) Its core functions include generating dynamic content and integrating with the database, allowing the website to be updated in real time and displayed in personalized manner. 3) The wide application and ecosystem of PHP have driven its long-term impact, but it also faces version updates and security challenges. 4) Performance improvements in recent years, such as the release of PHP7, enable it to compete with modern languages. 5) In the future, PHP needs to deal with new challenges such as containerization and microservices, but its flexibility and active community make it adaptable.

The core benefits of PHP include ease of learning, strong web development support, rich libraries and frameworks, high performance and scalability, cross-platform compatibility, and cost-effectiveness. 1) Easy to learn and use, suitable for beginners; 2) Good integration with web servers and supports multiple databases; 3) Have powerful frameworks such as Laravel; 4) High performance can be achieved through optimization; 5) Support multiple operating systems; 6) Open source to reduce development costs.


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