Business rules and script includes

  • Release version: Washingtondc
  • Updated February 1, 2024
  • 2 minutes to read
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    Summary of Business rules and script includes

    Business rules in ServiceNow are server-side actions executed during CRUD operations on instance records. They are essential for automating processes and enhancing application functionality.

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    Key Features

    • Execution Timing:
      • Before: Executes before the database operation to set or validate values.
      • After: Executes after the operation to trigger notifications or cascade updates.
      • Async: Runs as a separate process after the operation, suitable for longer tasks.
      • Display: Executes every time a form is displayed to prepare server-side data for client-side scripts.
    • Best Practices:
      • Keep business rules small and focused.
      • Avoid modifying base system business rules.
      • Utilize Script Includes for reusable logic instead of global business rules.
      • Use conditions to control the execution of business rules.
      • Refrain from using current.update() within business rules to prevent duplicate operations.
    • Script Includes: Store reusable JavaScript functions or classes that can be called from various server-side scripts, enhancing code modularity and efficiency.

    Key Outcomes

    By adhering to these guidelines, ServiceNow customers can improve application performance, maintain code reusability, and streamline their development processes, resulting in more efficient and manageable applications.

    Business rules are server-side actions that can be run during CRUD (Create, Read, Update, Delete) operations on instance records.

    Some good practices when using Business Rules are:

    • Keep Business Rules small and specific.
    • Avoid modifying base system Business Rules.
    • Use Script Includes instead of global Business Rules.
    • Use scripting only when necessary.
    • Store reusable script logic in a script include.
    • Use queries to limit records processed within a Business rule.
    • Avoid client-callable Business Rules to improve efficiency when running client scripts.
    • Always use a condition with Business Rules to control when the Business Rule runs. Running Business Rules with conditions can also aid in debugging. Business Rules rarely run with no conditions.

    Business Rules can be configured to run before or after a database operation. They can also be configured to run asynchronously and also before displaying a form or executing a query.

    Value Runs When to Use Example
    Before Synchronously before the database operation Set or update values on the current object as part of the save operation. Validate and abort execution if required. A developer wants to set the state of the current record based on another input in that record.
    After Synchronously after the database operation Trigger events and notifications after the database update to access the previous object or to make something occur in sequence. Update related records other than the base table being updated to access the previous object or to make something occur in sequence. A developer wants to cascade values from the current record down to child records.
    Async Asynchronously executed as a separate process after the database operation is completed The process triggered by the rule may take a while to run. When the user who triggered the operation does not need the output right away. Trigger events, notifications, or related record updates when access to the previous values of the record or a specific sequence of actions is not required. A developer needs to trigger an external process that may take a while or update a large number of records.
    Display Executed every time the corresponding form is displayed Used to make server-side objects available to client-side scripts. A developer wants to write information about a user associated with the current record to the g_scratchpad object to use in a client-side script.
    Note:
    current.update()should not be used in any Business Rules. Using current.update()triggers an additional database operation, which could cause duplicate notifications, recursive loops, etc.

    Use Script Includes to store JavaScript functions and classes for use by server scripts. Each Script Include defines either an object class or a function that can be reused among any server-side scripts. For more information, see Script includes.

    Store any code that might need to be used elsewhere in a Script Include. Call the Script Include from a Business Rule, UI Action, workflow script, Scripted REST API, etc. Instead of calling a Business Rule from a UI Action or a UI Action from a Scripted REST API, put the code in a Script Include and call the Script Include from both places.

    Keeping functions in a Script Include allows testing of the function before deploying the function in other scripted areas, thus reducing overall development and testing time.

    For more information, see Classic Business rules.