A Sequence defines a list of unique values.
The curValue and nextValue functions are used to get the current and next values in the sequence.
The following fields are configured on the Details tab:
| Field | Description |
|---|---|
| Name | The name of the sequence. |
| Start Value | The first value in the sequence. |
| Current Value | The highest value already allocated. |
The following fields are configured on the Advanced tab:
| Field | Description |
|---|---|
| Block Size | To configure the sequence to generate values without any gaps in the sequence, at the expense of increased database load, set the block size to 1. To improve performance, and allow gaps in the sequence of values, set the block size to a value greater than 1. |
The following fields are configured on the Description tab:
| Field | Description |
|---|---|
| Description | Free form text field to describe the Sequence. |
Form Icons
The form provides the standard form icons.
Example: Using a Sequence
To set a stream attribute to a unique order id:
- Create a Sequence named 'order_id'
- Create a Stream with an Integer attribute. Set its attribute expression to:
nextValue('order_id')
Every time a new record is generated in this stream, nextValue will return a new unique value.