Streamlining Data Retrieval in ServiceNow: The Power of Pagination with chooseWindow

[Amit Gujarathi]

Streamlining Data Retrieval in ServiceNow: The Power of Pagination with chooseWindow

Introduction

In the realm of ServiceNow development, efficiently managing and retrieving vast amounts of data is a common challenge. This is where the concept of pagination, particularly through the use of the chooseWindow function in GlideRecord, becomes invaluable. This article delves into why pagination is crucial in Scripted REST APIs, explains the pagination process, introduces the chooseWindow function, discusses its advantages, and walks through a practical use case.

The Need for Pagination in Scripted REST APIs

When dealing with extensive datasets, fetching all records in a single API call can overwhelm both the server and the end-user. It can lead to increased load times, higher consumption of system resources, and a suboptimal user experience. Pagination addresses these issues by dividing data into manageable chunks, allowing for the retrieval of a specific subset of data at a time.

Understanding Pagination

Pagination is a technique that divides content into separate pages, enabling users to navigate through data efficiently. By requesting only a portion of the data, applications can reduce loading times, conserve bandwidth, and improve user interaction, making it a critical feature for web and application development.

The chooseWindow Function in ServiceNow GlideRecord

ServiceNow's GlideRecord is an API used for querying database tables. The chooseWindow function within GlideRecord is particularly useful for implementing pagination. It allows developers to specify a range of records to return by setting a start and an end index, effectively slicing the dataset into pages without the need to retrieve all records first.

Advantages of the chooseWindow Function

The chooseWindow function offers several benefits:

• Improved Performance: By limiting the number of records processed and sent over the network, it significantly enhances the application's performance.
• Resource Efficiency: It reduces the load on the server by avoiding unnecessary queries for data that isn't immediately required.
• Enhanced User Experience: Users enjoy faster response times and a more responsive application, as data is loaded in smaller, more manageable portions.

Practical Use Case: Fetching Configuration Items with Pagination

Let's explore a practical application of pagination in a Scripted REST API designed to fetch Configuration Items (CIs) in ServiceNow. The API will utilize two parameters: pageSize and pageNumber, to control the volume of data returned per request.

Step 1: Create a Scripted REST API in ServiceNow, defining the necessary endpoints.

Step 2: Implement the logic to fetch CIs using GlideRecord's chooseWindow function. This involves calculating the start and end indexes based on the pageSize and pageNumber provided by the user.

Step 3: Test the API to ensure it returns the correct subset of data based on the pagination parameters.

This use case demonstrates how pagination, facilitated by the chooseWindow function, can significantly streamline data retrieval processes in ServiceNow, making it an essential technique for developers.

Conclusion

Pagination is a fundamental aspect of modern application development, crucial for handling large datasets efficiently. In ServiceNow, the chooseWindow function of GlideRecord offers a straightforward and effective method to implement pagination in Scripted REST APIs. By understanding and utilizing this function, developers can enhance application performance, reduce resource consumption, and improve overall user experience. As data continues to grow in volume and importance, mastering such techniques becomes indispensable in the toolkit of a proficient ServiceNow developer.

[Mwatkins]

Heads up, when using chooseWindow to introduce pagination you should also use setNoCount() to avoid an extra query. GlideRecord.chooseWindow causes GlideRecord to count all the records that match your query filter. You can avoid that extra query by using setNoCount().

See https://www.servicenow.com/community/developer-blog/optimizing-pagination-in-gliderecord-with-choose...

Please ✅ Correct if this solves your issue and/or 👍 if Helpful

"Simplicity does not precede complexity, but follows it" - Alan Perlis