Sequence Dialog v8
Use the Sequence
dialog to create a sequence. A sequence generates unique values in a sequential order (not necessarily contiguous).
The Sequence
dialog organizes the development of a sequence through the following dialog tabs: General
, Definition, and Security
. The SQL
tab displays the SQL code generated by dialog selections.
Use the fields in the General
tab to identify a sequence:
- Use the
Name
field to add a descriptive name for the sequence. The name will be displayed in theBrowser
tree control. The sequence name must be distinct from the name of any other sequence, table, index, view, or foreign table in the same schema. - Use the drop-down listbox next to
Owner
to select the name of the role that will own the sequence. - Use the drop-down listbox next to
Schema
to select the schema in which the sequence will reside. - Store notes about the sequence in the
Comment
field.
Click the Definition
tab to continue.
Use the fields in the Definition
tab to define the sequence:
- Use the
Increment
field to specify which value is added to the current sequence value to create a new value. - Provide a value in the
Start
field to specify the beginning value of the sequence. The default starting value is MINVALUE for ascending sequences and MAXVALUE for descending ones. - Provide a value in the
Minimum
field to specify the minimum value a sequence can generate. If this clause is not supplied or NO MINVALUE is specified, then defaults will be used. The defaults are 1 and -263-1 for ascending and descending sequences, respectively. - Provide a value in the
Maximum
field to specify the maximum value for the sequence. If this clause is not supplied or NO MAXVALUE is specified, then default values will be used. The defaults are 263-1 and -1 for ascending and descending sequences, respectively. - Provide a value in the
Cache
field to specify how many sequence numbers are to be preallocated and stored in memory for faster access. The minimum value is 1 (only one value can be generated at a time, i.e., no cache), and this is also the default. - Move the
Cycled
switch to theYes
position to allow the sequence to wrap around when the MAXVALUE or the MINVALUE has been reached by an ascending or descending sequence respectively. If the limit is reached, the next number generated will be the MINVALUE or MAXVALUE, respectively. The default isNo
.
Click the Security
tab to continue.
Use the Security
tab to assign privileges and define security labels for the sequence.
Use the Privileges
panel to assign privileges. Click the Add
icon (+) to set privileges:
- Select the name of a role that will be granted privileges from the drop-down listbox in the
Grantee
field. - Click inside the
Privileges
field. Check the boxes to the left of one or more privileges to grant the selected privilege to the specified user. - The current user, who is the default grantor for granting the privilege, is displayed in the
Grantor
field.
Click the Add
icon (+) to assign additional privileges; to discard a privilege, click the trash icon to the left of the row and confirm deletion in the Delete Row
popup.
Use the Security Labels
panel to define security labels applied to the sequence. Click the Add
icon (+) to add each security label selection:
- Specify a security label provider in the
Provider
field. The named provider must be loaded and must consent to the proposed labeling operation. - Specify a a security label in the
Security Label
field. The meaning of a given label is at the discretion of the label provider. PostgreSQL places no restrictions on whether or how a label provider must interpret security labels; it merely provides a mechanism for storing them.
Click the Add
icon (+) to assign additional security labels; to discard a security label, click the trash icon to the left of the row and confirm deletion in the Delete Row
popup.
Click the SQL
tab to continue.
Your entries in the Sequence
dialog generate a generate a SQL command (see an example below). Use the SQL
tab for review; revisit or switch tabs to make any changes to the SQL command.
Example
The following is an example of the sql command generated by user selections in the Sequence
dialog:
The example shown demonstrates a sequence named seconds
. The sequence will increase in 5
second increments, and stop when it reaches a maximum value equal of 60
.
- Click the
Info
button (i) to access online help. View context-sensitive help in theTabbed browser
, where a new tab displays the PostgreSQL core documentation. - Click the
Save
button to save work. - Click the
Cancel
button to exit without saving work. - Click the
Reset
button to restore configuration parameters.