Update fields.md

This documentation should provide developers with a clear understanding of how to create, configure, and manage custom database fields in Moodle 4.4.3.

docs/apis/plugintypes/mod_data/fields.md

@@ -1,81 +1,116 @@
+
 ---
-title: Database fields
-tags:
-  - mod_data
-  - datafield
-  - plugintype
-  - subplugin
-documentationDraft: true
+title: "Database Fields for Moodle 4.4.3"
+last_updated: "2024-10-02"
+tags: 
+  - "mod_data"
+  - "datafield"
+  - "plugin"
+  - "subplugin"
 ---
 
-The [Database activity](https://docs.moodle.org/en/Database_module) included with Moodle includes support for several predefined [field types](./fields.md), including text, date, and URL. It is also possible to create new field types. For example, you might like to create:
+# Database Fields for Moodle 4.4.3
+
+*This documentation is a work-in-progress. Feel free to contribute.*
+
+The **Database activity** in Moodle allows users to create structured collections of data. It supports various predefined field types like **text**, **date**, and **URL**. Developers can extend Moodle by creating custom field types, which are beneficial for specialized uses like discipline-specific, institution-specific, or module-specific needs.
+
+## Custom Field Types Examples
+
+- **Discipline-specific field types**:  
+  Example: "Protein PDB code" allows users to input a PDB code, displaying a 3D viewer of the protein structure or linking to molecular databases.
+
+- **Institution-specific field types**:  
+  Example: "Library reference number" allows users to input reference numbers that convert into direct links for local library services.
+
+- **Module-specific field types**:  
+  Example: "Wiki page" field provides a dropdown list of wiki pages, linking database entries to specific wiki content.
+
+## File Structure for Field Sub-Plugins
+
+Custom database field sub-plugins are located in `/mod/data/field`. Each plugin resides in a separate subdirectory and contains several required files.
+
+## Key Files for Field Plugins
 
-- Discipline-specific field types - For example "Protein PDB code": users can enter the PDB code for a protein, and then the display 3D viewer for the protein structure, or link out to molecular databases.
-- Institution-specific field types -  For example "library reference number": Allow users to enter a reference number which can be automatically turned into a direct link for local library services.
-- Module-specific field types - For example "wiki page": users see a drop-down list containing the names of pages in your wiki, and can choose which page this particular entry refers to.
+### 1. `field.class.php` (Required)
 
-import { ComponentFileSummary } from '../../../_utils';
+Defines the field type and its behaviors within a class named `data_field_[pluginname]`. This class must extend the `data_field_base` base class.
 
-## File structure
+### Key Functions to Override
 
-Database field sub-plugins are located in the `/mod/data/field` directory.
+- `display_add_field($recordid = 0)`: Generates HTML for adding or editing a record.
+- `display_browse_field($recordid, $template)`: Generates HTML for browsing records.
+- `update_content($recordid, $value, $name = '')`: Saves user input data.
+- `get_sort_sql($fieldname)`: Defines SQL for sorting records by the field.
+- `get_content_value($value)`: Retrieves and transforms the data for display.
 
-Each plugin is in a separate subdirectory and consists of a number of _mandatory files_ and any other files the developer is going to use.
+## Class Locations and Autoloading
 
-<details>
-  <summary>View an example directory layout for the `datafield_number` subplugin.</summary>
+Custom field definitions reside in `field.class.php`. **Moodle 4.4.3** does not autoload this file, so it is recommended to follow Moodle's [autoloading guidelines](https://moodledev.io/docs/guidelines/files/autoloading) to ensure future compatibility.
 
-```console
-mod/data/field/number
-├── classes
-│   └── privacy
-│       └── provider.php
-├── field.class.php
-├── lang
-│   └── en
-│       └── datafield_number.php
-├── mod.html
-└── version.php
+## Field Configuration Form
+
+**File Path:** `/mod.html` (Required)
+
+This file defines the form for adding or editing the field's configuration. Moodle's **Form API** is used to create input elements. Here is an example:
+
+```php
+$mform->addElement('text', 'fieldname', get_string('fieldname', 'datafield_[pluginname]'), 'size="30"');
+$mform->setType('fieldname', PARAM_TEXT);
+$mform->addRule('fieldname', null, 'required', null, 'client');
+```
+
+**Note**: The form retains some legacy elements, so developers are encouraged to update it to follow Moodle's [Form API guidelines](https://moodledev.io/docs/apis/core/dml/moodleform).
+
+## Security Best Practices
+
+When creating custom fields, ensure inputs are properly validated and sanitized. Use Moodle's security functions, such as `required_param()` and `optional_param()`, to prevent SQL injection and XSS attacks.
+
+Example:
+
+```php
+$input = required_param('input', PARAM_ALPHANUM);
 ```
 
-</details>
+## Testing and Compatibility
+
+Custom field plugins should be tested for compatibility across Moodle 4.4.3 supported environments, including:
 
-Some of the important files for the database field plugintype are described below. See the [common plugin files](../../commonfiles/index.mdx) documentation for details of other files which may be useful in your plugin.
+- **PHP 8.1**
+- **MariaDB 10.6.7**
+- **MySQL 8.0**
+- **PostgreSQL 13**
+- **MSSQL 2017**
+- **Oracle 19c**
 
-### Field class
+Use Moodle's [unit testing framework](https://moodledev.io/docs/apis/core/testing/phpunit) for automated testing to ensure functionality across different environments.
 
-<ComponentFileSummary
-    filepath="/field.class.php"
-    required
-    summary="Definition of the field type"
-/>
+## Form API Enhancements in Moodle 4.4.3
 
-The field, its behaviours, and its properties, are defined in a class named `data_field_[pluginname]` located in `field.class.php`. This class must extend the `data_field_base` base class.
+Moodle 4.4.3 introduces improvements to the **Form API** for better accessibility and user experience. Ensure that custom field forms are:
 
-:::danger Class locations
+- Mobile-responsive
+- Accessible
+- Optimized for modern browsers
 
-The field definition is currently located in the `field.class.php` file and is not yet autoloaded by Moodle.
+Follow Moodle's accessibility guidelines to make sure your forms work well for all users.
 
-:::
+## Version Control and Deployment
 
-The base class defines some simple behaviours which you can override in your plugin. The following functions are of particular interest:
+To ensure smooth development and deployment of custom field types:
 
-- `display_add_field($recordid = 0)` - Return some HTML for use when a user is adding/editing a record
-- `display_browse_field($recordid, $template)` - Return some HTML for displaying a record
-- `update_content($recordid, $value, $name = '')` - Store the data entered by a user for a record
-- `get_sort_sql($fieldname)` - Specify SQL for how this field should be sorted
-- `get_content_value($value)` - Useful if the info stored in the database if different from the info that ends up being presented to the user
+- Use Moodle's **Git version control** system.
+- Maintain proper versioning for compatibility with Moodle's plugin directory and version upgrades.
 
-### Field configuration form
+Developers should submit and maintain their plugins in the [Moodle Plugin Directory](https://moodle.org/plugins).
 
-<ComponentFileSummary
-    filepath="/mod.html"
-    required
-    summary="Form definition for adding and editing the field configuration"
-/>
+## Key Considerations for Moodle 4.4.3
 
-:::danger
+- Use **updated coding standards** to align with Moodle's guidelines for PHP 8.1.
+- Implement **security features** to avoid vulnerabilities.
+- Ensure **compatibility** across Moodle's supported environments.
+- Follow **best practices** for form creation and plugin configuration management.
 
-The field definition is one of the older parts of Moodle and does not use best practice.
+By following these guidelines, developers can ensure their custom field types are secure, modern, and compatible with future Moodle releases.
 
-:::
+**Last Updated**: 2 October 2024