Settings every field has

Besides its own Type settings (described on each type's page), every field has the same set of options. You find them by opening a field in WPM Fields › Field Groups and using the Advanced options panel of the field. The tabs are Type settings, General, Validation, Display and Conditional logic. Field groups explains the builder itself; this page explains how the options behave per type.

General tab

Default values

• The default is part of the database column, so it is applied when a row is created for the object, that is, the first time any field of the group is saved for that post, user or term. Until then the object has no row, and wpmcf_get_field() returns null (or the default argument you pass, see below).
• On the edit screen of a new object the control is prefilled with the default value.
• A default containing {{ expression }} (for example {{ wp.post_title }}) is evaluated per object on the edit screen and is not stored as the SQL column default; the column gets no default, so objects that never open the edit screen start empty.
• A default must fit the type. A Date or Time default must be a complete value in the column format (2026-01-01, 08:30:00); otherwise the group cannot be saved ("the default value does not fit this field type"). A Password never takes a default.
• A field with a SQL column function (for example upper or md5) cannot also have a default value. Clear it first.
• Types that store JSON (Checkboxes, Link, Map, Group, Repeater, Relationship, Taxonomy, User) and the long text types (Text area, URL, WYSIWYG, oEmbed) cannot carry a database default. For those the default can only prefill a control that accepts plain text (for example a Text area); set structured values in code instead.

Separate from this, wpmcf_get_field() accepts a default argument that is returned when the value is empty:

$phone = wpmcf_get_field( 'company', 'phone', $post_id, [ 'default' => 'Not available' ] );

The [wpmcf_field] shortcode accepts the same default="…". See Output, formats and escaping.

Constraints

On the server, required is a warning, not a block: when the classic editor saves a post with an empty required field, the post is saved and an admin notice says "Saved, but these required fields are empty: …". The block editor locks the Save button. Values written through wpmcf_update_field() or the REST API are not checked for required.

Validation tab

The Validation rules shown depend on the type.

What is enforced where:

The Validation tab also shows the field's column (Column: with its SQL type) and the SQL column options such as the SQL type override. Each type page lists which SQL types it allows.

Display tab

These options apply when a value is printed with wpmcf_the_field() or [wpmcf_field]. They do not affect wpmcf_get_field().

<!-- Prefix "$", suffix " USD", wrapper class "price" -->
<span class="wpmcf-field-value price">$19.9 USD</span>

The wrapper is a <span class="wpmcf-field-value">. Turn it off with wrap="false" (shortcode) or 'wrap' => false (PHP) to get the bare output. Prefix and suffix are escaped as plain text.

Conditional logic

The Conditional logic tab (Enable conditional logic, Add condition) shows or hides a field on the edit screen depending on other fields in the same group, at the same level (a sub-field can only depend on its sibling sub-fields).

• Combine rules with and (all must match) or or (any matches).
• Operators: has value, is empty, equals, not equals, contains, not contains, greater than, less than.
• Lists (Checkboxes, Relationship and similar) count as "has value" when at least one item is picked, and equals matches when one of the items equals the value. A True / false field compares as 1 (on) or 0 (off), so use equals 1 for "is on". Because 0 counts as a value, "has value" is true for a True / false field whether it is on or off.
• A rule that points at a field that does not exist passes.

Important behaviour:

• Hiding does not delete data. A hidden field still posts its stored value, so toggling a condition off and on never loses anything.
• A hidden field is never required, in the browser and on the server.
• Conditions only control the edit screen. Templates still read whatever is stored, so check the controlling field in your template if the hidden value should not be shown.

// Show the "reason" text only when the "refund" switch is on.
if ( wpmcf_get_field( 'order', 'refund' ) ) {
    wpmcf_the_field( 'order', 'reason' );
}

Variables in values

Text, Text area, Email and URL fields show a {} button on the edit screen to insert a {{ variable }} expression into the value. On output, expressions in these fields are resolved when the value's author is allowed to post unfiltered HTML. See Variables and hooks for the expression language. Values in comments are never resolved.

Troubleshooting

• "Field key is reserved" when saving the group: pick another key (see Field types overview).
• The default value does not show up in wpmcf_get_field(): the object has no row yet; save any field of the group for it, or pass the default argument.
• A rule seems ignored: only max length and min/max value are enforced on the server; see the table above.