YII Interview questions

1. What is Yii ?
Yii is a high-performance, component-based PHP framework for developing large-scale Web applications rapidly. It enables maximum reusability in Web programming and can significantly accelerate your Web application development process.

2. What are the requirements need for use Yii framework?
you need a Web server that supports PHP 5.1.0.
You also have knowledge on object-oriented programming (OOP).

3. What is Yii best for?
Yii is a generic Web programming framework that can be used for developing virtually any type of Web application. Because it is light-weight and equipped with sophisticated caching mechanisms, it is especially suited to high-traffic applications, such as portals, forums, content management systems (CMS), e-commerce systems, etc.

4. How to install Yii framework ?
Installation of Yii mainly involves the following two steps:
a. Download Yii Framework from yiiframework.com.
b. Unpack the Yii release file to a Web-accessible directory.

5. What command used to create new Yii project ?
% YiiRoot/framework/yiic webapp WebRoot/testdrive

6. Explain structure of Yii Project?

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testdrive/    index.php                 Web application entry script file    index-test.php            entry script file for the functional tests    assets/                   containing published resource files    css/                      containing CSS files    images/                   containing image files    themes/                   containing application themes    protected/                containing protected application files       yiic                   yiic command line script for Unix/Linux       yiic.bat               yiic command line script for Windows       yiic.php               yiic command line PHP script       commands/              containing customized 'yiic' commands          shell/              containing customized 'yiic shell' commands       components/            containing reusable user components          Controller.php      the base class for all controller classes          UserIdentity.php    the 'UserIdentity' class used for authentication       config/                containing configuration files          console.php         the console application configuration          main.php            the Web application configuration          test.php            the configuration for the functional tests       controllers/           containing controller class files          SiteController.php  the default controller class       data/                  containing the sample database          schema.mysql.sql    the DB schema for the sample MySQL database          schema.sqlite.sql   the DB schema for the sample SQLite database          testdrive.db        the sample SQLite database file       extensions/            containing third-party extensions       messages/              containing translated messages       models/                containing model class files          LoginForm.php       the form model for 'login' action          ContactForm.php     the form model for 'contact' action       runtime/               containing temporarily generated files       tests/                 containing test scripts       views/                 containing controller view and layout files          layouts/            containing layout view files             main.php         the base layout shared by all pages             column1.php      the layout for pages using a single column             column2.php      the layout for pages using two columns          site/               containing view files for the 'site' controller             pages/           containing "static" pages                about.php     the view for the "about" page             contact.php      the view for 'contact' action             error.php        the view for 'error' action (displaying external errors)             index.php        the view for 'index' action             login.php        the view for 'login' action

7. How to connect database on Yii Project?
To use a database, we need to tell the application how to connect to it. This is done in the application configuration fileWebRoot/testdrive/protected/config/main.php, highlighted as follows,

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return array(     ......     'components'=>array(         ......         'db'=>array(             'connectionString'=>'sqlite:protected/data/testdrive.db',         ),     ),     ...... );

8. How to configure gii web based code generator tool on Yii Project?
In order to use Gii, we first need to edit the file WebRoot/testdrive/protected/config/main.php, which is known as the application configuration file:

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return array(     ......     'import'=>array(         'application.models.*',         'application.components.*',     ),        'modules'=>array(         'gii'=>array(             'class'=>'system.gii.GiiModule',             'password'=>'pick up a password here',         ),     ), );

9. What is MVC ? Why need to use MVC?
MVC (Model – View- Controller ) is a design pattern., which is widely adopted in Web programming.
MVC aims to separate business logic from user interface considerations, so that developers can more easily change each part without affecting the other. In MVC, the model represents the information (the data) and the business rules; the view contains elements of the user interface such as text, form inputs; and the controller manages the communication between the model and the view.

10. How to change debug mode to production mode on yii project ?
Just define YII_DEBUG is false on entry script (root/index.php).

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// remove the following line when in production mode defined('YII_DEBUG') or define('YII_DEBUG',false); // include Yii bootstrap file require_once('path/to/yii/framework/yii.php'); // create application instance and run $configFile='path/to/config/file.php'; Yii::createWebApplication($configFile)->run();

11. How to set default controller on Yii Project ?
We can set on configuration file (protected/config/main.php).

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array(     'name'=>'Yii Framework',     'defaultController'=>'site', )

12. How to access application components on Yii Project ?
To access an application component, use Yii::app()->ComponentID, where ComponentID refers to the ID of the component (e.g. Yii::app()->cache).

13. What are the core application components available on Yii?
Yii predefines a set of core application components to provide features common among Web applications. For example, the request component is used to collect information about a user request and provide information such as the requested URL and cookies. By configuring the properties of these core components, we can change the default behavior of nearly every aspect of Yii.
Here is a list the core components that are pre-declared by CWebApplication:
• assetManager: CAssetManager – manages the publishing of private asset files.
• authManager: CAuthManager – manages role-based access control (RBAC).
• cache: CCache – provides data caching functionality. Note, you must specify the actual class (e.g.CMemCache, CDbCache). Otherwise, null will be returned when you access this component.
• clientScript: CClientScript – manages client scripts (javascript and CSS).
• coreMessages: CPhpMessageSource – provides translated core messages used by the Yii framework.
• db: CDbConnection – provides the database connection. Note, you must configure its connectionStringproperty in order to use this component.
• errorHandler: CErrorHandler – handles uncaught PHP errors and exceptions.
• format: CFormatter – formats data values for display purpose.
• messages: CPhpMessageSource – provides translated messages used by the Yii application.
• request: CHttpRequest – provides information related to user requests.
• securityManager: CSecurityManager – provides security-related services, such as hashing and encryption.
• session: CHttpSession – provides session-related functionality.
• statePersister: CStatePersister – provides the mechanism for persisting global state.
• urlManager: CUrlManager – provides URL parsing and creation functionality.
• user: CWebUser – carries identity-related information about the current user.
• themeManager: CThemeManager – manages themes.

14. Application Life Cycle of Yii framework ?
When handling a user request, an application will undergo the following life cycle:
1. Pre-initialize the application with CApplication::preinit();
2. Set up the class autoloader and error handling;
3. Register core application components;
4. Load application configuration;
5. Initialize the application with CApplication::init()
• Register application behaviors;
• Load static application components;
6. Raise an onBeginRequest event;
7. Process the user request:
• Collect information about the request;
• Create a controller;
• Run the controller;
8. Raise an onEndRequest event;

15. How to get current controller id in Yii ?
$controllerid = Yii::app()->controller->id;

16. How to get current action id in Yii ?
$actionid = Yii::app()->controller->action->id;

17. What is filter on Yii framework ?
Filter is a piece of code that is configured to be executed before and/or after a controller action executes. For example, an access control filter may be executed to ensure that the user is authenticated before executing the requested action; a performance filter may be used to measure the time spent executing the action.
An action can have multiple filters. The filters are executed in the order that they appear in the filter list. A filter can prevent the execution of the action and the rest of the unexecuted filters.
A filter can be defined as a controller class method. The method name must begin with filter. For example, a method named filterAccessControl defines a filter named accessControl. The filter method must have the right signature:

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public function filterAccessControl($filterChain) {     // call $filterChain->run() to continue filter and action execution }

18. What are the type of models available in Yii framework ?
Yii implements two kinds of models: Form models and active records. They both extend from the same base class,CModel.

19. What is CFormModel in Yii framework ?
A form model is an instance of CFormModel. Form models are used to store data collected from user input. Such data is often collected, used and then discarded. For example, on a login page, we can use a form model to represent the username and password information that is provided by an end user. For more details, please refer to Working with Forms.

20. What is CActiveRecord in Yii framework ?
Active Record (AR) is a design pattern used to abstract database access in an object-oriented fashion. Each AR object is an instance of CActiveRecord or of a subclass of that class, representing a single row in a database table. The fields in the row are represented as properties of the AR object. Details about AR can be found in Active Record.

21. What is the differences between render , renderPartial and renderfile in yii framework ?
render() is commonly used to render a view that corresponds to what a user sees as a “page” in your application. It first renders the view you have specified and then renders the layout for the current controller action (if applicable), placing the result of the first render into the layout. It then performs output processing and finally outputs the result. i.e) render with theme.
renderPartial() is commonly used to render a “piece” of a page. The main difference from render() is that this method does not place the results of the render in a layout. By default it also does not perform output processing, but you can override this behavior using the $processOutputparameter. i.e) render without theme.
renderFile() is a low-level method that does the grunt work of rendering: it extracts the data variables in the current scope and then runs the view code. The other two methods internally call this one, but you should practically never need to call it yourself. If you do, keep in mind that you need to pass in a file path (not a view path).

22. How to use widget on Yii framework ?
To use a widget, do as follows in a view script:

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beginWidget('path.to.WidgetClass'); ?> ...body content that may be captured by the widget... endWidget(); ?>

or

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1	widget('path.to.WidgetClass'); ?>

23. How to defining a component property in Yii ?
There are two different ways of defining a component property. First way is to simply declare a public member variable in the component class like the following:

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class Document extends CComponent { public $textWidth; }

Another way is to use getters and setters. It is more flexible since additionally to normal properties you can declare a read only or write only property.

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class Document extends CComponent { private $_textWidth; protected $_completed=false;   public function getTextWidth() { return $this->_textWidth; }   public function setTextWidth($value) { $this->_textWidth=$value; }   public function getTextHeight() { // calculates and returns text height }   public function setCompleted($value) { $this->_completed=$value; } }

The component above can be used like the following:

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$document=new Document();   // we can write and read textWidth $document->textWidth=100; echo $document->textWidth;   // we can only read textHeight echo $document->textHeight;   // we can only write completed $document->completed=true;

24. Why do Yii run so FAST?
Yii is so much faster because it uses sluggish loading technique widely. Like it doesn’t include a class file until the class is used initially and it doesn’t create object until it is accessed for the first time. Some of the frameworks get problems because of the performance hit because they would enable functionality no matter it is used or not during its request.

25. What about the naming convention in Yii?
The Yii Framework employees a class naming convention whereby the names of the classes directly plot to the directories in where they are stored. The root level directory of the Yii Framework is the “framework/” directory, where all classes are stored hierarchically. Class names contain alphanumeric characters.

26. what is the component, uses, how can we do and what is the better way?
A component is a piece of code written for specific task is used by calling controllers, helper is used for helping Yii in rendering the data to be shown to user with views, these adds to modularity in code or else same coding will be implemented in controllers.

27. What is the first function that gets loaded from a controller?
Index function. i.e) actionIndex()

28. What is meant habtm?
Habtm means HasAndBelongsToMany. The” has and belongs to many” is a kind of associations that defined in models for retrieving related data across different entities.

29. How to use ajax in Yii?
We use by calling ajax helper, then using it in controller for rendering.

30. What are the possible ways to validate a registrations module for a user in Yii?
This can be done in two ways by
i) submission in controller, or
ii) ii) using javascript/ajax while user is still filling the data. But, comparatively Second option will be better

31. List out some database related functions in Yii?
Query, find, findAll , findByPk , find By

32. How to include a javascript menu through a site?
We can include by adding the javascript files in webroot and then call them in default views if they are needed everywhere or in the related views.

33. Who was the developer of the Yii and when was it build?
The developer of the Yii is Yii Software LLC. It was started in the year 2008 in December 3, with the version of 1.0 and continued to 1.1.13. in PHP language.Yii is pronounced as Yee or [ji:], and is an acroynym for "Yes It Is!".Yii is a free, open-source Web application development framework written in PHP5 that promotes clean, DRY design and encourages rapid development.

Yii is the brainchild of its founder, Qiang Xue, who started the Yii project on January 1, 2008. Qiang previously developed and maintained the Prado framework. The years of experience gained and developer feedback gathered from that project solidified the need for an extremely fast, secure and professional framework that is tailor-made to meet the expectations of Web 2.0 application development. On December 3, 2008, after nearly one year's development, Yii 1.0 was formally released to the public.

Yii incorporates many ideas and work from other well-known Web programming frameworks and applications. Below is a short list of those from which Yii drew inspiration.

• Prado: This is the major source of ideas for Yii. Yii adopts its component-based and event-driven programming paradigm, database abstraction layers, modular application architecture, internationalization and localization, and many of its other features and patterns.
• Ruby on Rails: Yii inherits its spirit of convention over configuration. Yii also referenced its implementation of the active record design pattern for its ORM layer.
• jQuery: This is integrated in Yii as the foundational JavaScript framework.
• Symfony: Yii referenced its filter design and plug-in architecture.
• Joomla: Yii referenced its modular design and message translation scheme.

34. How does Yii Compare with Other Frameworks?
Comparatively to most of PHP frameworks, Yii is a MVC framework. Yii bests PHP frameworks for its efficient, feature-rich and clearly-documented. Yii is designed to be fit for serious Web application development. It is neither a consequence of some project nor a corporation of third-party work.

35. How do we extend Yii?
Extending Yii is a common action during web development. Like when we write a new controller, we extend Yii by inheriting its CController class; when we write a new widget, we will extend CWidget or an existing class. If the code is designed to be reused by third-party then we call it an extension.

36. What is a Yiibase?
YiiBase is a helper class that serves functionalities of common framework. We should not use YiiBase directly. Instead, have to use its child class where we can customize the methods of YiiBase.

37. How to generate CRUD code?
After creating a model class file, we shall generate the code that implements the CRUD operations for user data. We choose the Crud Generator in Gii. In the model class field, we enter ‘User’. In the Controller ID field, we enter ‘user’ in lower case. Then press the preview button followed by the Generate button. Now we are done with the CRUD code generation.

What is Yii Framework?

=>Yii is a high-performance component-based PHP framework best for Web 2.0 development.

What Yii is so FAST?

=> Yii is so much faster because it is using the lazy loading technique extensively. For example, it does not include a class file until the class is used for the first time; and it does not create an object until the object is accessed for the first time. Other frameworks suffer from the performance hit because they would enable a functionality (e.g. DB connection, user session) no matter it is used or not during a request.

Can you Remember what is directory structure when you downloaded Yii?  

    backend/

    common/

        components/

        config/

            params.php

            params-local.php *

        lib/

            Pear/

            yii/

            Zend/

        migrations/

        models/

            Comment.php

            Extension.php

            ...

    console/

        commands/

            SitemapCommand.php

            ...

        config/

            main.php

            main-local.php *

            params.php

            params-local.php *

        runtime/

        yiic.php *

    frontend/

        components/

        config/

            main.php

            main-local.php *

            params.php

            params-local.php *

        controllers/

            SiteController.php

            ...

        lib/

        models/

            ContactForm.php

            SearchForm.php     

        runtime/

        views/

            layouts/

            site/

        www/

            assets/

            css/

            js/

            index.php *

    yiic

    yiic.bat

What is the first file that gets loaded when you run a application using Yii?   

=>index.php

What is model,view,controller?                                                                     

=> Models represent the underlying data structure of a Web application. Models are often shared among different sub-applications of a Web application. For example, a LoginForm model may be used by both the front end and the back end of an application; a News model may be used by the console commands, Web APIs, and the front/back end of an application. Therefore, models

·         should contain properties to represent specific data;

·         should contain business logic (e.g. validation rules) to ensure the represented data fulfills the design requirement;

·         may contain code for manipulating data. For example, a SearchForm model, besides representing the search input data, may contain a search method to implement the actual search.

=> Views are responsible for presenting models in the format that end users desire. In general, views

·         should mainly contain presentational code, such as HTML, and simple PHP code to traverse, format and render data;

·         should avoid containing code that performs explicit DB queries. Such code is better placed in models.

·         should avoid direct access to $_GET, $_POST, or other similar variables that represent the end user request. This is the controller's job. The view should be focused on the display and layout of the data provided to it by the controller and/or model, but not attempting to access request variables or the database directly.

·         may access properties and methods of controllers and models directly. However, this should be done only for the purpose of presentation.

=>Controllers are the glue that binds models, views and other components together into a runnable application. Controllers are responsible for dealing directly with end user requests. Therefore, controllers

·         may access $_GET, $_POST and other PHP variables that represent user requests;

·         may create model instances and manage their life cycles. For example, in a typical model update action, the controller may first create the model instance; then populate the model with the user input from$_POST; after saving the model successfully, the controller may redirect the user browser to the model detail page. Note that the actual implementation of saving a model should be located in the model instead of the controller.

·         should avoid containing embedded SQL statements, which are better kept in models.

·         should avoid containing any HTML or any other presentational markup. This is better kept in views.

=> http://www.yiiframework.com/doc/guide/1.1/en/basics.best-practices

What is the naming convention inYii?                                                        

=> You can define table prefix when using Gii. In your case you need to set it to tbl_. Then it should  generate UserController instead of TblUserController.

=> The Yii Framework employs a class naming convention whereby the names of the classes directly map to the directories in which they are stored. The root level directory of the Yii Framework is the “framework/” directory, under which all classes are stored hierarchically.

Class names may only contain alphanumeric characters. Numbers are permitted in class names but are discouraged. Dot (.) is only permitted in place of the path separator.

What is the component,helper and why are they used,is there other way we can do same thing,what is better?

=> A component is an independent piece of code written for specific task that can be used by calling in controllers (example : email component), helper is used for helping yii in rendering the data to be shown to user with views, these only adds to modularity in code otherwise same coding can be implemented in controllers.

How do you proceed when you have to use Yii for any application?

=> take the framework either from Yii site or if you have changed according to your needs start from there. Proceed with basic software engg. concepts as requirement gathering etc..

This is a basic Understanding Concept in yii

1.    Yii-based apps are driven by data logic. When I build an app, I always start by making sure that my database schemes are well-designed and optimised to fit the business flow of the app. Therefore, my codes are automatically generated based on my database design. And, yes…

2.    … Yii can generate the whole shebang of PHP codes for you automatically! Just define which database you want to use, and with a few clicks it will create a CRUD (create-read-update-delete) app for you. It looks so cute, I tell you! Speaking of automatic…

3.    … Yii can generate a skeleton app for you automatically. This skeleton app include a view page, a login page, contact page and basic navigation, all wrapped within a completely organized folder tree based on the standard MVC programming model.

4.    The extensive choice of Yii functions makes sense. As a self-taught web programmer, I was able to map out its functions to all of the RESPONSE and REQUEST tasks I most often use when building webapps within a matter of minutes. It also doesn’t hurt that the Yii community has kindly provided cheat sheets for the functions so that I can do a quick reference when I need to.

5.    The Definitive Guide to Yii document that comes with the Yii install is actually quite easy to go through, at least for me. I don’t know why, though. I thought CakePHP docs were more user-friendly and attractive, but surprisingly I was able to go through Yii documentation and tutorial in just two hours and not get cross-eyed by the end of it.

6.    Yii uses MySQL and SQLite as its choice database types. Of course, you can run any other type of databases as long as you have its PDO enabled in your php.ini file. I develop using MySQL most of the time, but my fondness for SQLite is increasing, due to the fact that SQLite is so darn lightweight and easy to use.

7.    Yii is integrated with jQuery, which means that many of the necessary validation functions I use can easily be plugged within the Yii function calls itself, which is usually only a line of code or two.

8.    Yii is open-source, and it’s free. Open-source products turn me on.

What is the first function that gets loaded from a controller?               

=> index

 what is habtm?                                                                                                 

=>HasAndBelongsToMany

=>has and belongs to many is a kind of associations that can be defined in models for retrieving associated data across different entities.

11. How can we use ajax in Yii?                                                                                             

=>by calling ajax helper and then using it in controller for rendering.

12.If you have to validate a registrations module for a user, what all can be possible ways, which one is the best?

=>can be done on submission in controller, or using javascript/ajax while user is still filling the data. Second option is better.

13. can you list some database related functions in Yii?                                 

=> find, findAll , findByPk , find By ,query

14. How can you include a javascript menu throught the site? Give Steps…     

=>By adding the javascript files in webroot and call them in default views if needed everywhere or just in the related views.