Business Rule

                                                             ServiceNow Interview Questions

                                                                        Business Rule

1. What is a Business Rule in ServiceNow?

A Business Rule is a server-side script that runs when a record is inserted, updated, deleted, or queried. It is used to enforce business logic and automate processes.

2. What are the different types of Business Rules?

• Before: Executes before a record is saved to the database.
• After: Executes after a record is saved to the database.
• Async: Executes asynchronously after a record is saved.
• Display: Executes when a form is loaded and before the data is sent to the client.

3. When do Business Rules execute in ServiceNow?

Business Rules execute based on their type:

Before: Before the record is saved.

After: After the record is saved.

Async: After the record is saved, but runs in the background.

Display: When a form is loaded.

4. What is the difference between Before and After Business Rules?

• Before Business Rules run before the record is saved to the database, allowing you to modify the record before it is committed.
• After Business Rules run after the record is saved to the database, suitable for actions that do not need to modify the record being saved.

5. What are the advantages of using Async Business Rules?

Async Business Rules run in the background, minimizing the impact on user experience. They are ideal for time-consuming processes like data calculations, sending notifications, or integrations.

6. Can you call a Script Include from a Business Rule?

Yes, you can call a Script Include from a Business Rule to reuse code and maintain modularity. This helps in keeping the Business Rule code clean and manageable.

7. How do you debug Business Rules?

• You can use gs.log() or gs.debug() to log messages to the system log.
• Use the Script Debugger to step through the code and inspect variables.

8. What is the purpose of the current.update() method in Business Rules?

The current.update() method is used to save changes made to the current record. However, it should be used cautiously in Before and After Business Rules to avoid infinite loops.

9. What is the use of the setWorkflow(false) method in Business Rules?

The setWorkflow(false) method is used to prevent Business Rules and other workflows from running on the current record. This is useful to avoid triggering additional Business Rules or workflows when updating a record.

10. Can you explain the use of the current and previous objects in Business Rules?

The current object represents the record being processed, allowing you to access and modify its fields.

The previous object represents the state of the record before the current update, useful for comparing changes.

11. What is the difference between a synchronous and asynchronous Business Rule?

Synchronous Business Rule: Executes in real-time and the user waits for it to complete.

Asynchronous Business Rule: Executes in the background, allowing the user to continue working without waiting for it to complete.

12. Can you provide an example of a Business Rule that updates a field based on a condition?

Example of a Before Business Rule that updates the priority based on the impact and urgency:

JavaScript

if (current.impact == 1 && current.urgency == 1) {

    current.priority = 1;

}

13. What are the best practices for writing efficient Business Rules?

Best practices include:

Avoid using current.update() in Before and After Business Rules to prevent infinite loops.

Use gs.log() for debugging.

Keep scripts modular and reusable.

Optimize queries to reduce performance impact.

Use conditions to limit when the Business Rule runs.

Use asynchronous rules for long-running tasks.

14. How do you handle errors in Business Rules?

Handle errors by using try-catch blocks and logging error messages:

JavaScript

try {

    // Your code here

} catch (e) {

    gs.log('Error: ' + e.message);

}

15. How do you handle complex conditions in Business Rules?

Complex conditions can be handled using multiple if statements or logical operators (&&, ||). For example:

JavaScript

if (current.impact == 1 && current.urgency == 1) {

    current.priority = 1;

} else if (current.impact == 2 || current.urgency == 2) {

    current.priority = 2;

}

16. What is the use of gs.getUser() in Business Rules?

gs.getUser() returns the current user object, which can be used to get user details like user ID, roles, and other attributes. For example:

JavaScript

var user = gs.getUser();

var userID = user.getID();

var userName = user.getName();

17. How do you prevent a Business Rule from running multiple times on the same record?

Use the current.isNewRecord() method to check if the record is new, or set a flag field to ensure the rule runs only once. For example:

JavaScript

if (current.isNewRecord()) {

    // Business Rule logic

}

18. Can you explain the concept of previous object in Business Rules with an example?

The previous object holds the state of the record before the current update. It is useful for comparing changes. For example:

JavaScript

if (current.state != previous.state) {

    gs.log('State changed from ' + previous.state + ' to ' + current.state);

}

19. How do you use GlideAggregate in a Business Rule?

GlideAggregate is used to perform aggregate functions like COUNT, SUM, AVG, etc. For example:

JavaScript

var ga = new GlideAggregate('incident');

ga.addAggregate('COUNT');

ga.query();

if (ga.next()) {

    var count = ga.getAggregate('COUNT');

    gs.log('Total incidents: ' + count);

}

20. What is the difference between current.update() and current.setWorkflow(false) in Business Rules?

current.update() saves the current record to the database, potentially triggering other Business Rules and workflows.

current.setWorkflow(false) prevents the execution of workflows and Business Rules during the current update.

21. How do you handle exceptions in Business Rules?

Use try-catch blocks to handle exceptions and log errors. For example:

JavaScript

try {

    // Business Rule logic

} catch (e) {

    gs.logError('Error in Business Rule: ' + e.message);

}

22. Can you explain the use of gs.eventQueue() in Business Rules?

gs.eventQueue() is used to queue events for processing. It is useful for triggering notifications or other actions asynchronously. For example:

JavaScript

gs.eventQueue('incident.updated', current, current.sys_id, gs.getUserID());

23. What is the purpose of gs.addErrorMessage() in Business Rules?

gs.addErrorMessage() is used to display error messages to the user. It is often used in Before Business Rules to prevent record submission if certain conditions are not met. For example:

JavaScript

if (current.short_description == '') {

    gs.addErrorMessage('Short description is required.');

    current.setAbortAction(true);

}

24. How do you handle recursive Business Rules in ServiceNow?

Recursive Business Rules can cause performance issues and infinite loops. To handle them, use flags or conditions to ensure the rule does not call itself repeatedly. For example:

JavaScript

if (!gs.hasRun('myBusinessRule')) {

    gs.setRunFlag('myBusinessRule');

    // Business Rule logic

}

25. What is the use of gs.setAbortAction(true) in Business Rules?

gs.setAbortAction(true) is used to stop the current database operation. It is often used in Before Business Rules to prevent a record from being saved if certain conditions are not met. For example:

JavaScript

if (current.short_description == '') {

    gs.addErrorMessage('Short description is required.');

    gs.setAbortAction(true);

}

26. How do you use GlideElement in Business Rules?

GlideElement is used to interact with fields on a record. It provides methods to get and set field values, check if a field has changed, and more. For example:

JavaScript

var shortDesc = current.getElement('short_description');

if (shortDesc.changes()) {

    gs.log('Short description changed from ' + shortDesc.getPreviousValue() + ' to ' + shortDesc.getValue());

}

27. How do you use GlideSystem methods in Business Rules?

GlideSystem (gs) provides various utility methods for logging, adding messages, getting user information, and more. For example:

JavaScript

gs.log('This is a log message.');

gs.addInfoMessage('This is an info message.');

var userID = gs.getUserID();

28. How do you use GlideRecordSecure in Business Rules?

GlideRecordSecure is similar to GlideRecord but enforces ACL (Access Control List) rules. It is used when you need to ensure that the script respects user permissions. For example:

JavaScript

var gr = new GlideRecordSecure('incident');

gr.addQuery('priority', 1);

gr.query();

while (gr.next()) {

    gs.log('High priority incident: ' + gr.number);

}

29. What is the purpose of gs.getProperty() in Business Rules, and how do you use it?

gs.getProperty() retrieves the value of a system property. It is useful for accessing configuration settings. For example:

JavaScript

var myProperty = gs.getProperty('my.custom.property');

gs.log('Property value: ' + myProperty);

30. How do you handle large data sets in Business Rules to avoid performance issues?

To handle large data sets, use pagination or batch processing. For example:

JavaScript

var gr = new GlideRecord('incident');

gr.query();

while (gr.next()) {

    // Process each record

    if (gr.getRowCount() > 1000) {

        // Handle large data set

        break;

    }

}

31. Can you explain the use of gs.include() in Business Rules with an example?

gs.include() is used to include another Script Include within the current script. This allows for code reuse. For example:

JavaScript

gs.include('MyScriptInclude');

var mySI = new MyScriptInclude();

mySI.someFunction();

32. How do you use GlideDateTime in Business Rules to manipulate date and time fields?

GlideDateTime is used to work with date and time fields. For example:

JavaScript

var gdt = new GlideDateTime();

gdt.addDays(5);

current.due_date = gdt;

33. Scenario: You need to ensure that high-priority incidents are automatically assigned to a specific group. How would you achieve this using a Business Rule?

Create a Before Business Rule on the Incident table that checks the priority of the incident. If the priority is high, set the assignment group to the specific group.

JavaScript

if (current.priority == 1) {

    current.assignment_group = 'sys_id_of_specific_group';

}

34. Scenario: You want to prevent users from closing an incident if the resolution notes are empty. How would you implement this?

Create a Before Business Rule on the Incident table that checks if the state is being set to closed and if the resolution notes are empty. If so, add an error message and abort the action.

JavaScript

if (current.state == 7 && gs.nil(current.close_notes)) {

    gs.addErrorMessage('Resolution notes are required before closing the incident.');

    current.setAbortAction(true);

}

35. Scenario: You need to send a notification to the manager of the assigned user when an incident is reassigned. How would you set this up?

Create an After Business Rule on the Incident table that checks if the assigned_to field has changed. If it has, use gs.eventQueue() to trigger a custom event that sends the notification.

JavaScript

if (current.assigned_to.changes()) {

    gs.eventQueue('incident.reassigned', current, current.assigned_to.manager, gs.getUserID());

}

36. Scenario: You want to automatically update the short description of an incident to include the caller’s name when the incident is created. How would you do this?

Create a Before Business Rule on the Incident table that sets the short description to include the caller’s name.

JavaScript

if (current.isNewRecord()) {

    current.short_description = 'Incident reported by ' + current.caller_id.getDisplayValue();

}

37. Scenario: You need to ensure that incidents with a specific category are escalated to a higher priority if they are not resolved within 24 hours. How would you implement this?

Create a Scheduled Job that runs daily and checks for incidents with the specific category that are not resolved within 24 hours. Update the priority of these incidents.

JavaScript

var gr = new GlideRecord('incident');

gr.addQuery('category', 'specific_category');

gr.addQuery('state', '!=', 'resolved');

gr.addQuery('sys_created_on', '<=', gs.daysAgoStart(1));

gr.query();

while (gr.next()) {

    gr.priority = 1; // Escalate to high priority

    gr.update();

}

38. Scenario: You want to restrict the ability to delete records from a specific table to only users with the admin role. How would you achieve this?

Create a Before Business Rule on the specific table that checks if the current operation is delete and if the user has the admin role. If not, abort the action.

JavaScript

if (current.operation() == 'delete' && !gs.hasRole('admin')) {

    gs.addErrorMessage('You do not have permission to delete this record.');

    current.setAbortAction(true);

}

39. Scenario: You need to log changes to a specific field in a custom table for auditing purposes. How would you implement this?

Create an After Business Rule on the custom table that logs changes to the specific field.

JavaScript

if (current.field_name.changes()) {

    var log = new GlideRecord('audit_log');

    log.initialize();

    log.table_name = 'custom_table';

    log.record_id = current.sys_id;

    log.field_name = 'field_name';

    log.old_value = previous.field_name;

    log.new_value = current.field_name;

    log.insert();

}