What It Means

In JCB, field types are more than just form inputs — they are blueprint-driven entities that define how data is stored, validated, rendered, and interacted with. Each field type encapsulates both database schema and frontend/backend behavior, offering maximum reusability and consistency across views.

What It Is

Every field you create in JCB is based on a field type, which acts as a pre-configured template that dictates:

• The field’s data type (e.g., INT, VARCHAR, JSON, DATE)
• How it is rendered (text input, select box, calendar, etc.)
• What database structure it requires
• What validation and logic it applies during save/load
• Whether it’s editable, required, unique, nullable, etc.

JCB ships with dozens of Joomla-native field types and lets you define custom field types tailored to your component’s needs.

Key Features

• 📐 Structured Templates: Field types define the HTML and PHP rendering for each view (list/edit, admin/config), including layout and wrapper logic.
• 🧠 Central Rule Engine: Rules such as required, unique, readonly, default value, etc., are defined per field type and automatically applied wherever used.
• 📦 Consistent DB Schema: Fields derived from a field type automatically create matching SQL columns when compiled (unless overridden).
• 🔧 Reusable and Customizable: Field types can be reused across multiple views, components, or even exported/imported via blueprints.
• 🔁 Version-Aware Updates: JCB tracks field type changes and allows for safe resets, forks, or field type inheritance.
• 🌐 Joomla Compatibility: All native Joomla field types are supported and extended: text, select, calendar, editor, subform, repeatable, etc.

When You Use It

• Creating a new form field in a view
• Defining backend config fields or frontend submission forms
• Sharing complex input types (e.g., repeatable subforms, JSON maps)
• Linking fields to subviews or custom admin logic
• Implementing auto-validation on save

Use Cases

• ✅ A “Slug” field with unique + lowercase constraints
• ✅ A “Subregion selector” based on another view’s data
• ✅ A repeatable calendar field using subform
• ✅ A multiselect JSON-tag field for frontend filters
• ✅ A WYSIWYG editor only visible in Joomla 5

Best Practices

• Define new field types for any logic or structure used more than once
• Group similar field types using the Tags field inside JCB
• Use dynamic placeholders in rendering logic to adapt per context
• Leverage the field preview system when testing render logic

Conclusion

Field types are the building blocks of your component’s logic and data structure. JCB transforms them into fully automated renderers, validators, and schema generators — letting you control everything from user input to database schema with one powerful abstraction. Create once, reuse forever.