Understanding Tables in ServiceNow – A Complete Guide

[Abhishek_Thakur]

Introduction

Tables are the foundation of ServiceNow. Every piece of data — whether it’s an incident, a user record, or a custom business object — is stored in a table. Understanding how tables work, how they are related, and how to create and customize them is essential for every ServiceNow developer and administrator.

In this article, we’ll dive deep into the concept of Tables in ServiceNow, covering everything from the basics to best practices.

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🔹 What are Tables in ServiceNow?

A table in ServiceNow is a collection of records that store data in the form of fields (columns). Each record represents a single instance of data, and each field stores a specific type of information.

For example:

• The Incident [incident] table stores all incidents.

• The User [sys_user] table stores information about users.

• The Task [task] table acts as a parent table for several other tables like Incident, Problem, and Change Request.

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🔹 Types of Tables

ServiceNow tables can be broadly classified into three types:

1. Base Tables:
   These are independent tables that do not extend any other table. Example: cmdb_ci, sys_user.

2. Extended Tables:
   These tables extend other tables, inheriting their fields and functionality. Example: incident extends task.

3. Custom Tables:
   These are user-created tables for specific business requirements. You can define your own fields, access controls, and relationships.

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🔹 Table Hierarchy & Inheritance

ServiceNow follows a hierarchical table structure, where extended tables inherit the fields and properties of their parent tables.

For instance:
Task → Incident → Child Tables (if any)

When you open a record from an extended table (like Incident), ServiceNow fetches data from both the child and the parent tables — this process is known as table inheritance.

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🔹 sys_db_object – The Table of Tables

The sys_db_object table stores metadata for all tables in the platform.
You can navigate to it by typing sys_db_object.list in the application navigator.
It contains details such as:

• Table label and name

• Extends table reference

• Columns and attributes

• Access controls

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🔹 Creating a Custom Table

To create a new table:

1. Navigate to System Definition → Tables.

2. Click New.

3. Enter the label, which automatically generates the table name.

4. Define fields, relationships, and access controls.

Once saved, your new table becomes available in the system, and you can create forms, lists, and relationships for it.

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🔹 Best Practices for Working with Tables

✅ Always plan your table structure before creating it.
✅ Avoid extending the task table unless necessary — it impacts performance.
✅ Use meaningful field names and labels.
✅ Regularly review table relationships and dependencies.
✅ Leverage Dictionary Overrides and Field Decorations wisely.

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📽️ Watch the Full Video

If you’d like to see a step-by-step walkthrough with practical examples, check out my detailed YouTube video:
🎥 Understanding Tables in ServiceNow | Complete Guide for Beginners

Regards,

Abhishek Thakur

[Bert_c1]

You're missing what is described in the documentation:

Table Flattening

and information on changing field types.

[Maroof Ali]

Good Article