Unique data rule checks whether there are any records with the same value as in the validated cell that appear in the following rows. Therefore, the first duplicate value in the field will be added to error list.
This rule can be particular useful for validation of a primary key field.
To add Unique data rule for single field to the schema:
- double click on the field in the list to open Field Details form;
- click with the right mouse button on the Rules node in the rules tree;
- select in the pop-up menu;
- click on the OK button:
Now all duplicate records in this field will be highlighted in the error list.
If you want to create a unique constraint on several fields:
- double click on existing Unique constraint;
- in the Unique Constraint form choose Select Unique Columns option;
- check columns that should be included in the constraint;
- select the index column in the drop down list an click on OK button:
