Drupal Pages and Views: CCK Computed Field

In this short article, I am going to share with you what Jess Snyder is doing with her sites by using the CCK computed field module. With this method, you can create a content type that is designed to display content from a view after the node has passed an argument to the view.

Sample Scenario

Assume you have an educational site. On this site you have a content type for instructor and a content type for course. When you create an instructor node, you want the courses that instructor teaches listed below the instructor’s bio. You don’t want to have to remember which courses you just want the list to appear.

In order to make this happen, you need an instructor content type that has a view. The view will create a list of courses based on the instructor’s node ID. You also need a course content type that allows you to connect the instructor to the course. Assume that there is a one-to-one match between instructor and course.

This process can be accomplished several ways. For one, you could use the node relativity module (node_relativity) which allows you to create parent-child relationships between nodes. But this module limits what gets displayed to the node title. The method below enables you to control what you see in the view (one field or multiple fields)

Pre-requisites

In order to use this method, you will need CCK (enable the node reference option) and Views installed as well as the computed field module. You will also need to know how to create content types with CCK fields and Views. If you need help with CCK or Views, check out the resources at the following links:

• http://learnbythedrop.com/category/cck
• http://learnbythedrop.com/category/views

Steps

Below is a summary of the steps you need to perform. Details regarding the computed field configuration are provided below the steps.

1. Create an instructor content type. At this time, just use the defaults settings.
2. Create a course content type.
   1. Add a node reference field.
   2. When configuring the node reference field, select the instructor content type to be referenced.
   3. If you assume a one-to-one relationship between the instructor and the course, leave the number of values setting = 1.
3. Create an instructor node.
4. Create a course node and reference the instructor node.
5. Create a node view.
   1. Filter the nodes to list all nodes with content type = course.
   2. Set the fields to node title (at the least) and check the option to “Link this field to its node.”
   3. Include an argument to limit list results to only those with instructor node ID. The NID is what gets passed by the computed field to the view.
   4. Note: you can call the default view in the computed field so you don’t have to create a block or page.
6. Edit the instructor content type.
   1. Add the computed field.
   2. Set up the field computed code and display format. In this scenario, you would use:
      1. Computed code: $node_field[0]['value'] = $node->nid;
      2. Display format: $display = views_embed_view('nameofview', 'default', $node_field_item['value']);
   3. Set the database storage setting.
      1. Data type = int
      2. Date length = 11 (because you only need to store the NID, you don't need a long length. It just needs to hold the argument that will be passed to the view. )
   4. If you position this field below the node body, the view results will show below the body. If you want the view results to appear above the node body, re-order the content type fields.
   5. If you do not want the label of the computed field to appear when the page is viewed, change the display settings for the computed field.
7. Go to the instructor node you created earlier. Click edit and save to get the new field to show up. View the instructor node and see that the course link appears as well.

Computed_field Information

When you add the computed_field to your content type, you are taken to the configuration screen. In the Global settings box you will see two forms: computed code and display format.

Computed Code

The form provides this statement:

The variables available to your code are: &$node, $field, and &$node_field. To set the value of the field, set $node_field[0]['value']. Here's a simple example which sets the computed field's value to the value of the sum of the number fields field_a and field_b: $node_field[0]['value'] = $node->field_a[0]['value'] + $node->field_b[0]['value'];

The code provided in the instructions above (and below) is consistent with these instructions.

$node_field[0]['value'] = $node->nid;

If you are new to coding, let’s look at each part of this statement.

• $node_field[0]['value'] – this is a variable. The variable gets assigned a value that will be sent to the view.
• [0] – set the first value of the array to zero
• ['value'] - the value of the field

If you don’t want to use the NID, you could also assign the value of another field in the content. If, for example, you have a content type that that has a status field. An you want to show a view that shows all other nodes with the same status, you could assign the $node_field[0]['value'] variable to be the value of the status field. Your view would then be designed to show all nodes with the status value argument.

Display Format

The form provides this statement:

This code should assign a string to the $display variable, which will be printed as the value of the field. The stored value of the field is in $node_field_item['value']. Note: this code has no effect if you use the "Computed Value" formatter option.

The code provided in the instructions above was provided with the Views module. Jessica looked at the functions available in the views.module file.

$display = views_embed_view('nameofview', 'default', $node_field_item['value']);

If you are new to coding, let’s look at each part of this statement.

• $display – this is a variable whose value gets deplayed by the computed_field module.
• views_embed_view() – views function from views.module
• nameofview – this is the $name of the view
• default – this is the $display_id of the view
• $node_field_item['value'] – this is an additional parameter. Notice that it is the computed code variable. The first thing that happens is, this variables gets assigned a value that, in this case, is an argument that the view needs. Then, the value of the variable is sent to the view.

Summary

As you can imagine, you can do a lot with the computed_field module. Jessica has found a convenient way to make a connection between between books and authors on http://www.thebookstudio.com".

Drupal Pages and Views: Insert View Module

This article considers the insert view module as a means of adding a view to a page. With this method, you don't need a unique content type, you just need to enable the insert_view filter. This is probably the easiest way to insert a view into your page.

Sample Scenario

Assume that you have several members of your staff writing articles for your company site. Your articles happen to cover several topics and have been tagged accordingly. You have decided to write an article about the articles and want to include tables of articles through out your narrative.

Your approach is to introduce the first topic, talk about why that topic is important to your company, and then follow up with a table displaying the articles posted in the last month. You want the title, date, and author. Your narrative continues by introducing the next topic and why it is important to your company, another table is inserted and so on.

The easiest way for a non-programmer to insert Views within the body of a page narrative is to use the Insert_View module.

Pre-requisites

In order to use this method, you will need the Insert View Module, and Views installed. You will also need to know how to create a view. If you need help with views, check out this resource:

• http://learnbythedrop.com/category/views

Steps

In the case of the insert_view module, the readme.txt file does a nice job explaining how to install and configure the module. The steps below reflect one way to install and configure the insert_view module. This "formula" is based on the tips and instructions found in the readme.txt file.

Create an input format. "To display views correctly, Insert View turns off caching for the input formats for which it is enabled. That means every node using this input format will not be cacheable. This can impact site performance. In these cases, it is recommended to create a special input format for use when inserting views."

1. After enabling the insert-view module, go to site configuration > input format > add input format.
2. Give it a name like "insert_view"
3. Decide if this input format is going to be restricted to a specific role.
4. Check the boxes for each filter you want to apply to this input format, including the insert view filter.
5. Save the configuration.

Create a view. The insert_view module allows you to simply insert a view as is, in its default mode or you can be more specific. If you want to be more specific, please review the following insert_view filter configurations and plan accordingly.

Default
[view:my_view] - Name of the view (this is not the title or the path).

Specific Display
[view:my_view=my_display] - When in the view's edit mode, locate the list of displays at the left side of the control area. "Defaults" will be at the top of that list. Hover your mouse pointer over the name of the display you want to use. A URL will appear in the status bar (at the bottom) of your browser. Everything after #views-tab- is the display ID.

Include an Argument
[view:my_view=my_display=1,2,3] - This passes a comma delimited argument to your chosen display.
[view:my_view==1] - This passes a comma delimited argument to the default.

Create a node.

1. Type your content into the body of your node.
2. Type the applicable filter. For example, assume you are using the page display of a view called "listtopic." This view requires a taxonomy term ID and you want term #25. In the body, you would type [view:listtopic=page_1=25]
3. Repeat steps 1 and 2 if you want more.
4. Select the applicable input filter (if you chose to create a separate input format)
5. Save.

Summary

This approach is fairly straight forward. If you aren't a programmer but want to manage how your text and views appear on the screen, you can try using an HTML to manage the layout. For example, if you have two lists, you can create a 2-column table and place an insert_view tag in each column. Here is an example http://postharvesthub.vudat.msu.edu/?q=node/18.

Drupal Pages and Views: CCK View Reference Field

In this short article, I am going to look at using the view reference module as a means of adding a view to a page. With this method, you can create a content type that has an option to display content from a view. You can use a view as is or pass it an argument. The sections below present a sample scenario, steps for implementing view reference, and a layout tip.

Sample Scenario

You have a web site where you have multiple content authors contributing their ideas, information, stories, and so on. The content authors can post up to five types of content (designated, in the case, by a taxonomy vocabulary) each associated with 10 topics (also designated by a taxonomy vocabulary).

You want to put the content posts into context by writing a story or scenario that explains why the topic is valid and how it relates to the other topics on the site. You want your text to be followed by a list of related content posts that are tagged with the topic you are writing about.

This process can be accomplished several ways. For one, you could simply create a page view and use the header area of the page view to show story or scenario. In this case, let’s assume two things:

• You want the text of your story or scenario to look like your other nodes and you don’t feel like tweaking your theme in the event the View header ends up looking different than your other pages.
• You aren't the only one creating context pages. You think there is going to be others wanting to do the same. You need a method that allows the content authors access to the views without having to open the Views UI.

Pre-requisites

In order to use this method, you will need CCK, the View Reference Module, and Views installed. You will also need to know how to create content types with cck fields and views. If you need help with cck or views, check out the resources at the following links:

• http://learnbythedrop.com/category/cck
• http://learnbythedrop.com/category/views

Steps

Below is a summary of the steps you need to perform in order to support the scenario above.

1. Create the view(s) you need for your stories or scenarios.
   1. You can create 10 separate views, one for each topic
   2. OR you can create one view with a topic argument
2. Create a content type (use an existing content type). In our sample scenario, maybe call it context page.
   1. Add a view reference field.
   2. When choosing the "form element to edit the data," you can use a select list (good for users who don't know the name of the views they can choose) or autocomplete text field.
   3. When configuring the view reference field, check the views that you want available in the content type. There will be a list available to choose from.
3. Create your node with the new content type. By default, you will see the text you entered in the body followed by the results of the view.

Layout Tip

If you want to control the layout of the fields in your node, check out the composite module.

"Composite Layout allows your nodes to be displayed in complex layouts. Currently, two and three column layouts are provided. You can also add other nodes, blocks, and even CCK fields to your node's layout. The content area of your node is divided into zones and you decide what should appear in those zones. Zones are essentially the same as Drupal blocks, but they apply to nodes rather than the entire site."

Summary

You have some things to think about. For example, do you want to use arguments in your views? Also, don't forget your permissions. Who will be able to use this new content type? Remember to think through the process of how this strategy will be used and by whom. Sometimes the best solution for you is not the best solution for your users.