Where to Set up?

On the form design page, select the Lookup field, and configure it in the Field Properties.

Selecting the Master Form

The master form is the form you want to establish a relationship with. Supported types include:

Intra-Form Hierarchical Relationship: Select the current form.
Inter-Form Relationship: Select another form within the same app (cross-app relationships are not supported).

In Field Properties > Select a Form to Relate to, select a form from the drop-down list as your master form.

Notes:

1. You must have admin permission to the selected master form to configure it.

2. Once saved, the master form cannot be changed.

3. A related tab will be automatically added to the master form’s data detail page for viewing and managing related records.

4. Limits:

Only one intra-form hierarchical relationship can be configured per form.
A single form can be the master form of up to 50 forms.
A single form can contain up to 20 Lookup fields.

5. When copying forms, a validation will be triggered for the number of relationships:

Not exceeding the limit: relationships are retained in the copied form.
Exceeding the limit: relationships are removed and must be reconfigured manually.

Selecting Data

Select Data defines what and how data from the master form is selectable and displayed through the Lookup field.

There are three buttons under Select Data:

Display Fields
Filter Conditions
Settings: click the button and jump to a new page for additional configurations. Real-time preview is available on the left side of the settings page.

Let's dive into the additional settings on the settings page!

Button Label

By default, the field displays the label “Lookup”. You can customize it under Button Label. Once data is selected, the button label displays the title of the selected record.

Fields and Records to be Displayed

This feature defines what information is shown in the data selection list. Click the box and check the fields to be shown from the drop-down list. You can also reorder or rename them.

Filter Conditions

You can restrict which records are selectable by setting filter conditions.

Click the Filter button and configure the following options:

When there are multiple filter conditions, you can choose to match all of or any of the conditions.
Field from the master form: also include system fields (e.g., Submitter, Submission Time).
Condition type: e.g., equals, does not equal, contains, is empty.
Field value: choose a field from the current form or enter a custom value.

After all configurations, click OK.

Data Sorting Rule

To prioritize certain records for easier selection, configure data sorting rules:

Fields that support sorting include:
- Form Fields: Single Line, Number, Date&Time, Radio, Single Select, Serial No., Aggregation
- System Fields: Submission Time, Updated Time, WeChat OpenID, etc.
Order: Ascending or Descending

Data Permission

Configure data visibility in the Data Permission section:

View all data (default): All records in the master form are visible.
View permitted data only: Users can only see records they have permission to view in the master form.

Note:

This permission setting only affects the data selection process and not other areas.

Operation on the Master Form

If this option is enabled, you can directly add new records to the master form on the current page when no matching data is found.

Data Filling

Add Rule

Data filling allows field values from the selected master form to be copied into the current form when filling out the form. Click Add Rule to choose fields from the master form and define how they will be filled:

Fill into new field: Automatically create a new field in the current form and fill in the master form record.
Fill into existing field: Manually map master form records to existing fields.

Notes:

1. Unsupported field types: Divider, Query Data, Select Data, Signature, Button.

2. When filling into new fields, for Radio/Single Select field, the form will create or be filled into the same type of field; for Serial No. field, it will create or be mapped into a Single Line field only.

3. If a field has a formula or data linkage rule, it cannot configure data filling rules, and vice versa.

Card Display Field

Card display field allows selected master form data to be displayed in card form without saving it to the current form or using it in formulas. It will display:

Below the Lookup field during form filling
On the detail view page of the form entry

Notes:

1. Subform fields from the master form are not supported.

2. You must have the view permissions on the selected fields.

3. These fields do not count toward the form's field limit. For details, see Fields.

Initial Value

Lookup field supports the following initial value types:

None: The initial value is empty.
Data Linkage: Automatically populates the field using data from another form that meets certain conditions.

You can click Data Linkage Settings to configure the initial value:

If the linked form is the master form of this Lookup field, use the Data ID from the master form as the default.
If the linked form shares a Lookup field with the same master form, you can use that shared field value for the default.