Release 10.1A: OpenEdge Development:
Basic Database Tools

Sequence Editor option

Use the Schema Sequence Editor menu option to view, define, modify, and delete sequences. Sequences are database objects that provide sequential values within any integer range and with your choice of increment. When you choose this option, a window similar to the one shown in Figure 9–16 appears.

Figure 9–16: Sample Sequence Editor window

The Sequence Editor displays the existing sequences and the following attribute fields:

Name

Enter a valid identifier as a name for your sequence. The name can be up to 32 characters long.

Initial Value

Enter an initial integer value for the sequence, or accept the default of 0. The initial value becomes the lower limit if the Increment By value is positive and becomes the upper limit if the Increment By value is negative. You cannot specify an initial value that is greater than your upper limit or less than your lower limit, if defined.

Increment By

Enter a positive or negative integer value by which you want to change the sequence value at each increment, or accept the default of 1. If you enter a positive value, then each increment increases the sequence toward a defined upper limit. If you enter a negative value, then each increment decreases the sequence toward a defined lower limit, and the Upper Limit label changes to Lower Limit.

Upper Limit or Lower Limit

Enter an integer value to define the upper or lower limit of the sequence, or accept the default value of unknown (?). If you specify a positive value for the Increment By field, you can only define an upper limit. If you specify a negative value, you can only specify a lower limit. You cannot specify an upper limit that is less than the initial value. Likewise, you cannot specify a lower limit that is greater than the initial value. If you accept the default, the Sequence Editor uses the maximum integer value on your system as the defined upper limit and the minimum integer value as the defined lower limit.

Cycle at limit

Indicates whether the sequence becomes a cycling or terminating sequence. A cycling sequence restarts at the initial value when it reaches the upper limit or decrements beyond its lower limit, providing non-unique values for the life of the sequence. A terminating sequence stops incrementing when it reaches the upper limit or stops decrementing when it reaches its lower limit, providing unique values as long as you do not explicitly reset it. The default is no, indicating a terminating sequence.

DataServer Name

For non-OpenEdge databases only. Displays the name of the corresponding non-OpenEdge sequence, if there is one.

Owner

For non-OpenEdge databases only. Displays the name of the user who has permission to access the sequence.

Besides the attribute fields listed above, the Sequence Editor lists options along the bottom of its display. Table 9–19 describes these options.

Table 9–19: Sequence Editor options 

Option	Description
Next	Displays the next sequence.
Prev	Displays the previous sequence.
>NextPage	Displays the next set of sequences.
<PrevPage	Displays the previous set of sequences.
First	Displays the first sequence.
Last	Displays the last sequence.
Add	Adds a new sequence.
Modify	Updates sequence attributes.
Delete	Deletes the selected sequence.
Undo	Undoes changes you made to the sequence structures during this session.
Exit	Saves your changes, exits the Sequence Editor, and returns to the Data Dictionary main window.