Forms: Sequence

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.

Form: Sequence Details

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.

The form provides the standard form icons.

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.