Field Attributes

Field Attributes in ServiceNow - Complete Study Guide

What are Field Attributes?

Field attributes in ServiceNow are properties that define the behavior, appearance, and functionality of individual fields within a table. They control how data is entered, displayed, validated, and stored in the database. Every field in ServiceNow has a set of configurable attributes that determine its characteristics.

Why are Field Attributes Important?

Understanding field attributes is crucial for several reasons:

• Data Integrity: Proper field configuration ensures accurate and consistent data entry
• User Experience: Attributes control how forms appear and behave for end users
• Business Logic: Many attributes enforce business rules at the database level
• Performance: Indexed fields and proper attribute settings improve query performance
• Security: Attributes can control field-level access and visibility

Common Field Attributes Explained:

Type: Defines the data type (String, Integer, Date/Time, Reference, Choice, etc.)

Max Length: Specifies the maximum number of characters allowed in a field

Mandatory: When set to true, the field must contain a value before the record can be saved

Read Only: Prevents users from modifying the field value on forms

Display: Controls whether the field appears on forms and lists

Active: Determines if the field is currently in use

Unique: Ensures no duplicate values exist in this field across all records

Default Value: Automatically populates the field with a specified value for new records

Reference: Links the field to another table (for Reference field types)

Reference Qualifier: Filters the available options in a reference field

Dependent: Creates relationships between choice fields

Calculated: Indicates the field value is computed rather than entered

How Field Attributes Work:

1. At the Database Level: Attributes like type and max length define how data is stored in the underlying database schema

2. At the Form Level: Attributes control field behavior on forms, including mandatory indicators, read-only status, and default values

3. At the Application Level: ServiceNow processes field attributes during record operations to enforce validation rules and business logic

Accessing Field Attributes:

• Navigate to System Definition > Tables
• Select the desired table
• Click on the field name in the Columns related list
• View and modify the Dictionary Entry form

Alternatively, right-click on any field label on a form and select Configure Dictionary

Exam Tips: Answering Questions on Field Attributes

1. Know the Core Attributes: Focus on understanding Mandatory, Read Only, Unique, Max Length, and Default Value as these appear frequently in exam scenarios

2. Understand Reference Fields: Be prepared to explain how reference qualifiers filter related records and how the reference attribute links tables together

3. Distinguish Between Similar Concepts: Know the difference between making a field read-only through dictionary attributes versus using UI policies or ACLs

4. Remember the Dictionary Entry: Questions often ask where field attributes are configured - the answer is typically the Dictionary Entry or sys_dictionary table

5. Practice Scenario Questions: When given a requirement like ensure no duplicate email addresses, recognize this requires the Unique attribute

6. Default Value Syntax: Know that default values can include JavaScript using javascript: prefix for dynamic values

7. Calculated Fields: Understand that calculated fields store computed values and are typically read-only

8. Max Length Implications: Remember that changing max length on existing fields with data requires careful consideration

Common Exam Scenarios:

• Setting a field as mandatory for data quality requirements
• Configuring reference qualifiers to limit selection options
• Understanding when to use unique constraints
• Identifying the correct location to modify field attributes
• Choosing appropriate field types for specific data requirements