Client sites keep extra details on each entry: a job title on a team member, a price on a course, an ISBN on a book. These live in custom fields, and Delta does not know they exist until you tell it.
A field map is that introduction. You point Delta at one custom field and give it a short name. The agent can then place that value anywhere in your design, and every entry fills in its own.
Set one up
Ask the agent for it in plain words:
“Add a field map so the {course_level} custom field shows up as {level}.”
That is the whole setup. From then on, {{level}} in a template prints the course level of whichever course the visitor is looking at.
What you can map
| You have | Delta gives you |
|---|---|
| A text field | The text |
| A field with formatted content | The formatted content |
| A link field | The link |
| An image field | The image, ready to place |
| A category or tag group | A list you can loop over |
| A field holding other entries | A list you can loop over |
The first four print a single value. The last two give you a list, so the agent repeats a piece of markup once per item, using the same loops you use elsewhere in Delta.
An example
A client sells courses. Each course carries a level, a badge image, and a set of topics.
Ask for three maps:
“Add field maps for courses: {level} from the course level field, {badge} from the badge image, and {topics} from the course topics.”
One template for all courses can now show all three: the title, the level, the badge, and a list of topic links. Add a course, fill in its fields, and the page is complete. You do not touch the template again.
If a field is empty on one entry, that spot is simply blank. The page still works.
Where to see them
Go to Delta → Field Maps in wp-admin for the full list. You can add and edit maps there by hand, and filter them by post type.
Maps you create yourself are marked manual. When the agent builds a new content type for you, Delta writes the matching maps at the same time and marks them synced.
For developers
A map binds a post meta key, or a taxonomy, to a placeholder. The six types are text, html, url, image, terms and posts. terms reads a taxonomy; the rest read post meta. An image map also exposes {{name_url}} for the raw URL, and an html map expands shortcodes.
Names use lowercase letters, digits and underscores, and cannot reuse a name Delta already owns, such as title or permalink. Maps are site-wide unless you scope them to post types. The abilities are delta/list-field-maps, delta/get-field-map, delta/upsert-field-map and delta/delete-field-map.