Create a Domain Rule

This topic describes how to create a domain rule in Data Quality Services (DQS). A domain rule is a condition that is used to validate, correct, and standardize domain values. A domain rule must hold true across a domain in order for domain values to be considered accurate and conformant to business requirements. Domain rules can include validation rules that are used to validate domain values, but are not used to correct data in a data quality projects. Rules also include standardization rules that are applied against valid data and are used in data correction.

In This Topic

• Before you begin:

  Prerequisites

  Security

• Build Domain Rules

• Test Domain Rules

• Apply Domain Rules

• Follow Up: After Creating a Domain Rule

• Domain Rule Conditions

Before You Begin

Prerequisites

To create a domain rule, you must have a knowledge base and a domain opened in the Domain Management activity.

Security

Permissions

You must have the dqs_kb_editor or the dqs_administrator role on the DQS_MAIN database to create a domain rule.

[Top]

Build Domain Rules

1. Start Data Quality Client. For information about doing so, see Run the Data Quality Client Application.

2. In the Data Quality Client home screen, open or create a knowledge base. Select Domain Management as the activity, and then click Open or Create. For more information, see Create a Knowledge Base or Open a Knowledge Base.

   Note

   Domain management is performed in a page of the Data Quality Service client that contains five tabs for separate domain management operations. It is not a wizard-driven process; any management operation can be performed separately.

3. From the Domain list on the Domain Management page, select the domain that you want to create a domain rule for, or create a new domain. If you have to create a new domain, see Create a Domain.

4. Click the Domain Rules tab.

5. Click Add a new domain rule, and then enter a name that is unique in the knowledge base and a description for the rule.

6. Select Active to specify that the rule will be run (the default), or deselect to prevent the rule from running.

7. In the Build a Rule pane, select a condition from the drop-down list in the rule’s clause box.

8. If the condition requires a value, enter the value in the associated text box.

9. Click Adds a new condition to the selected clause icon if another clause is required.

10. Select AND or OR as the operator.

11. Select a condition from the drop-down list and then enter a value for the operand, if required.

12. To change the order in which the clauses appear in the list, select a clause and then click the up or down arrow. This will change the order in which they are executed, which could affect the results.

13. Add more clauses as required. If needed, delete a clause by selecting it and then clicking Deletes the selected clause.

14. Repeat to add new rules, as necessary.

15. To see the impact that a validation rule would have on values if implemented, click the Analyze the domain rule impact on the domain values icon.

16. Proceed to the test procedure below.

[Top]

Test Domain Rules

1. With one rule selected, click the Run the selected domain rule on test data icon.

2. In the Test Domain Rule dialog box, click the Add a new testing term for the domain rule icon. Enter a value to test. Enter other values as required. Select a value and click the Remove the selected testing term icon if required.

3. Click the Test the domain rule on all the terms icon.

4. Check the validity of each term. A check means “correct”, a cross means “error”, and a triangle means “invalid”.

5. Click Close when done in the testing dialog box.

6. Repeat for other rules, as necessary.

7. Proceed to the application procedure below.

[Top]

Apply Domain Rules

1. Click Apply All Rules to apply the rules to the values in the domain. Apply you click Apply All Rules, a popup will be displayed indicating how many values in certain states will be affected by the rule. Click Yes if you still want to apply the rule, or No if not. If you click Yes, click OK to close the results popup.

   Note

   When you create or change a rule, you do not need to save the changes. However, you must apply the rule for the changes to take effect.

2. Click Discard All Changes to remove any changes that you have made to domain rules, reverting to the previously applied rules, with the result that any changes made after the last application of the rules will no longer apply. The validity of each value in the domain will be updated to be in accordance with the previously applied rules, not the discarded changes.

3. Click Finish to complete the domain management activity, as described in End the Domain Management Activity.

[Top]

Follow Up: After Creating a Domain Rule

After you create a domain rule, you can perform other domain management tasks on the domain, you can perform knowledge discovery to add knowledge to the domain, or you can add a matching policy to the domain. For more information, see Perform Knowledge Discovery, Managing a Domain, or Create a Matching Policy.

[Top]

Domain Rule Conditions

The table below describes the conditions that can be applied in the domain rule, and provides example to illustrate how the conditions can be applied.

When a domain rule is applied and a domain value fails the rule, the value is designated Invalid. A value that is designated Invalid will be changed to Correct if the rule causing it to be invalid is deleted, is deactivated, or the rule has been changed such that the value no longer fails the rule. If you have designated a value as Invalid manually (in the Domain Values tab of the Domain Management activity), and a rule that the value fails has been deleted, deactivated, or changed, then the value will still be designated Invalid, in accordance with the manual designation.

A domain rule that has a definitive condition will apply the rules logic to synonyms of the value in the condition or conditions, as well the values themselves. The definitive conditions are Value is equal to, Value is not equal to, Value is in, or Value is not in. For example, suppose you have the following domain rule: “For ‘City’, Value is equal to ‘Los Angeles’”. If ‘Los Angeles’ and ‘LA’ are synonyms, both will be correct. On the other hand, if your rule did not contain a definitive condition, such as “For City, Value ends with “s”, then “Los Angeles” would be correct, but its synonym “LA” would be in error.

You have alternatives to choose from in creating a domain rule. For example, to validate whether values begin with the letter A, B, or C, you could create a simple rule with a complex condition (such as a regular expression with pipe characters), or you could create a complex rule that contains several simple conditions. An example of the first rule is “Value contains regular expression (^A|^B|^C)”. An example of the second rule is “’Value begins with A’ OR ‘Value begins with B’ OR ‘Value begins with C’”.

[Top]