Create, read, update and delete (CRUD) are the four basic operations of persistent storage. In our blog application, the major task is to implement the CRUD operations for both posts and comments. In this section, we will use the yiic
tool to accomplish this task. This process is also known as scaffolding.
Open a command window and run the following commands:
% /wwwroot/yii/framework/yiic shell /wwwroot/blog/index.php Yii Interactive Tool v1.0 Please type 'help' for help. Type 'exit' to quit. >> model User ...... >> model Post ...... >> model Tag ...... >> model Comment ...... >> crud Post ...... >> crud Comment ...... >> exit
Info: Some PHP installations may use a different
php.ini
file for command line (CLI) PHP parser. As a result, when running the aboveyiic
commands, you may encounter errors like "YiiBase::include(PDO.php): failed to open stream..." or "...could not find driver". Please double check your CLI PHP configuration by executing the following command:php -r "phpinfo();"The result of the above command will show which
php.ini
file is being used and which extensions are loaded. If a wrongphp.ini
file is used, you may use the following command to explicitly specify the correctphp.ini
to use:php -c php.ini /wwwroot/yii/framework/yiic.php shell /wwwroot/blog/index.php
The commands above accomplish two tasks. First, the model
commands generate a model class file for each database table. Second, the crud
commands generate the code needed by the CRUD operations for the Post
and Comment
models.
We can test the generated code by accessing the following URLs:
http://www.example.com/blog/index.php?r=post http://www.example.com/blog/index.php?r=comment
Notice that the post and comment features implemented by the generated code are completely independent of each other. Also, when creating a new post or comment, we are required to enter information, such as authId
and createTime
, which in real application should be set by the program. Don't worry. We will fix these problems in the next milestones. For now, we should be fairly satisfied as this prototype already contains most features that we need to implement for the blog application.
To prepare for the next milestones, let's take a closer look at the files generated by the above commands. All the files are generated under /wwwroot/blog/protected
. For convenience, we group them into model files, controller files and view files:
model files:
models/User.php
contains the user
class that extends from CActiveRecord and can be used to access the User
database table;models/Post.php
contains the Post
class that extends from CActiveRecord and can be used to access the Post
database table;models/Tag.php
contains the Tag
class that extends from CActiveRecord and can be used to access the Tag
database table;models/Comment.php
contains the Comment
class that extends from CActiveRecord and can be used to access the Comment
database table;controller file:
controllers/PostController.php
contains the PostController
class which is the controller in charge of all CRUD operations about posts;controllers/CommentController.php
contains the CommentController
class which is the controller in charge of all CRUD operations about comments;view files:
views/post/create.php
is the view file that shows an HTML form to create a new post;views/post/update.php
is the view file that shows an HTML form to update an existing post;views/post/show.php
is the view file that displays the detailed information of a post;views/post/list.php
is the view file that displays a list of posts;views/post/admin.php
is the view file that displays posts in a table with administrative commands.views/post/_form.php
is the partial view file that displays the HTML form for collecting post information. It is embedded in the create
and update
views.In order to understand better how the above files are used, we show in the following the workflow that occurs in the blog application when displaying a list of posts:
PostController
and executes it;PostController
instance executes the requested list
action by calling its actionList()
method;actionList()
method queries database to bring back the list of recent posts;actionList()
method renders the list
view with the post data.
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