3.4.1.3 Unique Keys Pane

Specifies one or more unique constraints for the table.

A unique constraint specifies a column, or set of columns, whose data values must be unique: each data value must not be null, and it must not be the same as any other value in the column.

To add a unique constraint, click the Add button; to delete a unique constraint, select it and click the Remove button.

• Name: Name of the unique constraint.

• Enabled: If this option is selected, the unique constraint is enforced.

• Rely: If this option is selected, the constraint in NOVALIDATE mode is taken into account during query rewrite.

• Deferrable: If this option is selected, in subsequent transactions, constraint checking can be deferred until the end of the transaction using the SET CONSTRAINT(S) statement.

• Initially Immediate: If this option is selected, the constraint is checked at the end of each subsequent SQL statement.

• Validate: If the option is selected, the existing data is checked to see if it conforms to the constraint.

• Index: Name of the index to which the unique key refers.

• Tablespace: Name of the tablespace associated with the index.

• Available Columns: Lists the columns that are available to be added to the unique constraint definition.

• Selected Columns: Lists the columns that are included in the unique constraint definition.

To add a column to the unique constraint definition, select it in Available Columns and click the Add (>) icon; to remove a column from the unique constraint definition, select it in Selected Columns and click the Remove (<) icon. To move all columns from available to selected (or the reverse), use the Add All (>>) or Remove All (<<) icon. To move a column up or down in the unique constraint definition, select it in Selected Columns and use the arrow buttons.