docs/docs/en/data-sources/field-sequence/index.md
In NocoBase, Sequence generates business numbers.
It is suitable for order numbers, contract numbers, work-order numbers, and application numbers that need readable rules. Unlike a primary key, it is intended for business display and manual identification. Use Snowflake ID, UUID, or Nano ID for internal unique identifiers.
Sequence fields are suitable for these business scenarios:
On the collection's Configure fields page, click Add field and select Sequence to create this field.
| Setting | Description |
|---|---|
| Field interface | The field interface. Sequence uses sequence, which determines how the field is entered and displayed in pages. |
| Field display name | The name displayed for the field, such as Order number, Contract number, or Work-order number. Use a name that business users can recognize. |
| Field name | The field identifier used internally by APIs, relation fields, permissions, and workflows. It usually cannot be changed after creation. It supports only letters, numbers, and underscores, and must begin with a letter. |
| Field type | The data-layer type. Sequence uses string by default. |
| Default value | The default value. When a new record has no value, NocoBase can fill this value automatically. |
| Validation rules | Validation rules. Is normally generated by the system according to rules and does not need manual validation. |
| Description | A field description. Record the field meaning, entry requirements, data source, or maintainer. |
:::warning Note
Field names are referenced by page blocks, permissions, workflows, and APIs after creation. Confirm the name before creating the field to avoid later configuration changes.
:::
The default behavior of a Sequence field is as follows:
| Behavior | Description |
|---|---|
| Default Field interface | sequence. |
| Default Field type | string. |
| Available Field types | string. |
| Page component | Displays a value generated according to sequence rules. |
| Filtering | Supports text filters where supported by the data source. |
| Sorting | Supports sorting in Table blocks. |
| Validation | Is normally generated by the system according to rules and does not need manual validation. |
After creation, click Edit beside the field to edit its configuration. Edit fields to adjust how they are displayed and used in NocoBase, such as the display name, description, default value, validation rules, or field-specific settings.
When a field comes from a synchronized main-database table, editing usually maps the database field to a NocoBase Field type and Field interface.
| Setting | Can be edited | Description |
|---|---|---|
| Field display name | Yes | Changes the name displayed in the interface without changing the field identifier. |
| Field name | No | The field identifier normally cannot be changed in the edit form after creation. |
| Field interface | Conditional | Main-database fields and synchronized fields can be adjusted during field mapping. Changes affect page input, display, and validation. |
| Field type | Conditional | Main-database fields and synchronized fields can be adjusted during field mapping. Confirm that existing values can be used by the new type first. |
| Default value | Yes | Adjusts the default value for new records. |
| Validation rules | Yes | Adjusts field validation rules. |
| Description | Yes | Adds the field meaning, entry requirements, data source, or maintainer. |
:::warning Note
Changing a Field type or Field interface is more than changing a display name. It affects field storage, input components, validation rules, filters, and workflow-variable usage. When the field contains substantial existing data, confirm that its data format is compatible first.
:::
Click Delete beside a Sequence field to delete it. You can also select multiple fields and delete them in the main data source.
Deleting a Sequence field created in the main database usually also deletes the actual database column and its values. For a synchronized or external-data-source field, the impact depends on the corresponding data source and field origin.
:::danger Warning
Deleting a field can affect page blocks, forms, filters, permissions, workflows, APIs, imports and exports, and existing data. Confirm that the field is no longer referenced by business configuration before deleting it.
:::
Sequence fields are suitable for readable business identifiers in pages and documents.
| Scenario | Use |
|---|---|
| Details block | Display a business number. |
| Table block | Display, sort, and filter business numbers. |
| Forms | Show a generated number where supported. |
| Workflows and APIs | Use a business number in integrations. |