Sequences Wizard (DB2 LUW)
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A sequence allows the automatic generation of values, something well-suited to the generation of unique key values. Sequences are not tied to particular table columns. The Sequence Wizard lets you create a sequence without knowing the underlying commands. As you complete the Sequence Wizard, a CREATE SEQUENCE statement is generated from the information that you have supplied. When finished, you can compile the sequence on the target database or to write a script file containing the CREATE SEQUENCE statement.
The Sequence Wizard lets you:
- Specify the name and owner of the sequence.
- Set both the value of the sequence, and an interval and ranges for incrementing it.
- Cache the sequence, cycle the sequence when it reaches its minimum or maximum values, and guarantee that sequence numbers are generated in the order of request.
- Note: To create a sequence, it must belong to your schema or you need CREATE SEQUENCE privileges.
To Open the Sequence Wizard
- On the Navigator/Explorer, find the datasource where you want to add the new Sequence.
- Expand the Schema branch, right-click Sequences, and select New.
The table that follows describes what you may encounter as you complete the Sequence Wizard:
| Required Information | Description |
|---|---|
|
Who owns the sequence? |
You decide. |
|
What is the sequence name? |
Your choice. |
|
What numeric datatype should the Sequence use? |
Choose among BIGINT (big integer), decimal (choose width as well), integer, small integer. |
|
What is the first sequence number to be generated? |
Starting with 1 is the default. |
|
What is the interval between sequence numbers? |
Increment by 1 is the default. |
|
What is the sequence’s minimum value? |
Choose none or set a value |
|
What is the sequence’s maximum value? |
Choose none or set a value |
|
Should DB2 preallocate sequence numbers and cache them for faster access? |
Preallocating and storing values in the cache reduces synchronous I/O to the log when values are generated for the sequence. If Yes, give number of values No |
|
Should the sequence continue to generate values after reaching either its maximum or minimum value? |
Lets you make the sequence cycle and continue to generate numbers. Yes or No |
|
Should the sequence numbers be generated in the order of request? |
Select to generate sequence numbers in the order of request. The ORDER option is useful when you are using the sequence number as a timestamp. Yes or No |