Content classes for websites
This page is for website creators who create or adapt the content classes of a site in the administration. It covers the class editor, the settings of a class and of each attribute, and which changes are safe once the site holds content.
Contents
- Where classes live
- Create a class
- Class settings
- Attribute settings
- Changing a class on a live site
- Moving classes between installations
Where classes live
Setup > Classes (/class/grouplist) lists the class groups (Content, Users, Media, Setup); each group lists its
classes (Class groups). The classes of a new installation come from the site
package (Site packages and the themes that ship).
Create a class
From 2. Create a class:
- Open Setup > Classes, the group Content, then New class.
- Give a name (
Event) and an identifier (event). - Set the object name pattern, for example
<title>. - Add attributes: choose a datatype under Add attribute, press Add, give a name and an identifier.
- Press OK. The class can now be created wherever policies allow.
Class settings
| Setting | What it does |
|---|---|
| Name, identifier | what editors read; what templates and overrides use |
| Object name pattern | builds each object's name from attributes: <title>, <first_name> <last_name>, <short_title|title> (the first that is not empty) |
| URL alias name pattern | builds the URL alias; empty means the object name |
| Container | the class may have children |
| Default sorting of children | the sort order new objects of this class give their children |
| Default object availability | whether an object is shown in languages it was not translated into ("always available") |
Attribute settings
| Setting | Use |
|---|---|
| Required | the object cannot be published while it is empty |
| Searchable | the attribute's text goes into the search index |
| Translatable | each language has its own value; turn off for prices, dates, codes |
| Information collector | the attribute is filled in by visitors, not editors (Forms with the information collector) |
| Category | groups attributes into tabs of the edit form |
| Datatype options | depend on the datatype: maximum length, default value, allowed classes for relations, image size limit ... |
Two datatype options were added in Exponential 6 and are worth knowing for websites (9. Required alternative text ...): image fields can require an alternative text, and text lines can trim the stored value.
Changing a class on a live site
| Change | Safe? | Note |
|---|---|---|
| Add an attribute | yes | existing objects get an empty value; check templates handle empty |
| Rename an attribute's name | yes | the identifier stays |
| Change an identifier | risky | every template and fetch using it must change at once |
| Make an attribute required | yes, but | existing objects stay as they are until edited |
| Remove an attribute | destructive | the data of that attribute is deleted from every object |
| Change a datatype | not possible in place | add a new attribute, migrate the data, remove the old one |
| Move an attribute up or down | yes | only the edit form order |
Warning
Large classes with many objects take a while to change, because every object gets the new attribute. Make class changes outside busy hours, and with a backup (Backups and restores).
Moving classes between installations
Do not rebuild classes by hand on the production site. Export them from the development installation as a package and import it (Content packages (.ezpkg), Packages). Identifiers and remote IDs keep templates and overrides working on both sides.
Related pages
- Designing your content model
- Choosing datatypes for your fields
- The content model and editing
- Free documentation: this page is free to copy, translate and improve under the GNU FDL 1.3.
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