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ServiceNow Table Administration Interview Questions 2024

ServiceNow Table Administration and its developers and administrators are in demand. I am presenting questions related to ServiceNow Table Administration basics which are essential from an interview point of view.

Please go through it and give your best in the interview.

What is the ServiceNow table?

  • A table is a collection of records in the database.
  • Each record corresponds to a row in a table, and each field on a record corresponds to a column on that table.
  • The Now Platform uses a table-based data structure to store and organize information.
  • Pre-built tables are included for common IT service management (ITSM) processes, with their data fully importable and exportable in CSV, XML, or other formats.
  • Admins can also create custom tables for specific business requirements, define field properties, create relationships between tables, and extend existing tables without modifying the originals.

What are servicenow out-of-box tables?

  • Tables created by servicenow in the now platform.
  • Examples- incident, problem, task,cmdb_ci etc
  • admins can’t delete these tables.

What are custom tables in ServiceNow?

  • These are the tables created by the admins of the company
  • It starts with u_tableName
  • We can delete/modify these tables

What is a table extension in ServiceNow?

  • In serviceNow, it is possible to establish parent-child relations between tables.
  • Enable one or more child tables to share fields and records with a parent table.
  • A table that extends another table is called a child class, and the table it extends is the parent class.
  • A table can be both a parent and child class both extending and providing extensions for other tables.
  • A parent class that is not an extension of another table is called a base class.
  • Administrators and application developers can only extend tables during table creation
  • We see many such relations in a base system such as task and incident, task and problem etc

What are the ways to see the relation between ServiceNow classes?

  • Administrators can use these tools to see the relationships between classes.
    • Schema map
    • System dictionary
    • Tables module

What are the different extension models in ServiceNow?

  • The Now Platform offers these extension models.
    • Table per class
    • Table per hierarchy
    • Table per partition

What are schema maps in servicenow tables?

  • The schema map displays the details of tables and their relationships in a visual manner
  • Allowing administrators to view and easily access different parts of the database schema.
  • The schema map can also be printed directly from a browser

Which database in Servicenow supports rollback and recovery?

What is the delete records module in ServiceNow?

  • This module is used to recover deleted records from the servicenow instance.
  • This module works on records in audited tables.
  • Cascaded deleted records must be recovered within seven days of the record deletion.
  • After seven days, only data records and references on tables that audit deletions can be recovered, which is the same functionality as prior releases

How to recover script execution details under the Scripts – Background module?

  • Navigate to Rollback & Recovery > Script Execution History

What are rollback context?

  • Rollback contexts contain everything necessary to roll back a software upgrade or plugin activation.
  • They include deleted records, patch updates, Scripts-Background script executions, database actions, and plugin activations.
  • A rollback context is created for each patch upgrade within a family, and each plugin activation, provided that the plugin supports rollback contexts.
  • Activate the Restore Deleted Records and Delete Recovery plugins to use rollback contexts.

When a rollback context is created in the servicenow instance?

A rollback context is created when:

  • GlideRecord.delete() or GlideRecord.deleteMultiple() delete records.
  • There is a patch upgrade.
  • You activate a plugin that supports rollback contexts.
  • A script executes using the Scripts-Background module, and rollback was enabled by
    selecting the Record for Rollback. check box.

What are the database limitations in Servicenow?

  • Certain Now Platformsubscriptions include custom table entitlements.
  • You can create custom tables for any purpose, up to the entitlement limit in the subscription.
  • The system can only have a maximum of 1000 columns per table.
  • Every table, regardless of the storage engine, has a maximum row size of 65,535 bytes
  • The system can’t have more than 10 medium-length or longer String fields to a single table
  • When you create fields, the u_ prefix is automatically added to the column name.

What is ServiceNow dictionary override?

  • Dictionary overrides allow you to define a field on an extended table differently from the field on the parent table.
  • For example, for a field on the Task [task] table, a dictionary override can change the default value on the Incident [incident] table without affecting the default value on Task [task] or on Change [change].
  • Administrators can override these aspects of a field:
    • Reference qualifiers
    • Dictionary attributes
    • Default values
    • Calculations
    • Field dependencies
    • Default column display values
    • Mandatory and read-only status

Can we change the type of a field in ServiceNow?

  • You can change the type of a field.
  • To preserve existing data, only change between logical types that map to the same physical type on the database.
  • For example, Choice and String

What are functional fields in ServiceNow?

  • A field that displays the results of a database function, such as a mathematical operation, field length computation, or day-of-the-week calculation.
  • Once the new function record is saved, you cannot clear the check box to make the field a regular field.
  • Video tutorial:- https://youtu.be/zjpOIxxXnSI

What is a calculated field?

  • This Determines whether the value of the field is calculated from other values.
  • The Calculation Type field allows you to select the script or formula-based calculation for the column value.
  • About business rules, calculated fields are populated first before any business rule, even a business rule, is run.
  • Fields display as read-only when calculated scripts are applied.

Can I remove the attribute of the base system?

  • Yes, you can remove it.
  • If you remove an attribute that is part of the base system, it is automatically restored during an upgrade.
  • To prevent upgrades from changing your system’s behavior, leave the attribute on the table or field but set its value as desired.
  • For example, if a field has the attribute knowledge_search=true by default, do not remove it to set it to false; rather, set it to knowledge_search=false.

What are the preconditions in naming a custom table in ServiceNow?

  • For a table in a scoped application, the name is prefixed with a namespace identifier to indicate that it is part of an application.
  • For a table in the global application, the name is prefixed with the string u_
  • For a remote table in a scoped application, the name is prefixed with a namespace identifier and the string st_ to indicate that it is remote and part of an application.
  • For a remote table in the global application, the name is prefixed with the string u_st_
  • You cannot modify the prefix; however, you can modify the rest of the table name.
  • The name can contain only lowercase, alphanumeric ASCII characters and underscores (_).

What is the purpose of “display” checkbox in the dictionary record?

  • It indicates whether this field is the Display values(appears on records that reference this table).

What is the purpose of “Can Read” checkbox in the application section of table?

  • Select the check box to enable script objects from other application scopes to read records stored in this table.
  • This option offers runtime protection.
  • For example, a script in another application can query data on this table. First select read access to grant any other API record operation.

What is the purpose of “Can Create” checkbox in the application section of table?

  • Select the check box to enable script objects from other application scopes to create records in this table.
  • This option offers runtime protection.
  • For example, a script in another application can insert a new record in this table.
  • This option is available only when the Can read check box is selected.
  • Clear the check box to prevent script objects from other application scopes from creating records in this table.

What is the purpose of “Can Update” checkbox in the application section of table?

  • Select the check box to enable script objects from other application scopes to modify records stored in this table.
  • This option offers runtime protection.
  • For example, a script in another application can modify a field value on this table.
  • This option is available only when the Can read check box is selected.
  • Clear the check box to prevent script objects from other application scopes from modifying data stored in this table.

What is the purpose of “Can Delete” checkbox in the application section of table?

  • Select the check box to enable script objects from other application scopes to delete records from this table.
  • This option offers runtime protection.
  • For example, a script in another application can remove a record from this table.
  • This option is available only when the Can read check box is selected.
  • Clear the check box to prevent script objects from other application scopes from deleting records from this table.

What is the purpose of “Allow Configuration” checkbox in the application section of table?

  • Select the check box to enable applications from other application scopes to create configuration records for this table that change its functionality.
  • For example, an application designer can select this table from the Tables list on
  • business rules, client scripts, or UI actions.
  • This option offers design-time protection.
  • Clear the check box to prevent application designers from selecting this table when creating configuration records.

What are system fields in ServiceNow?

  • When you create a new custom table, several fields appear in the Table Columns embedded list.
  • For all tables, required system fields are added automatically.
  • You cannot delete or modify these fields.
  • For tables that extend another table, fields on the parent table also appear on the Table Columns embedded list for the current table.
  • If you modify these fields, remember that all changes to fields on the parent table affect all child tables, not just the current table.

Can we delete a table in ServiceNow?

  • Administrators can delete custom tables that are no longer needed.
  • A table is custom if an administrator created it and it is not part of a system upgrade or plugin activation
  • Custom table names always begins with u_, or x_ for scoped tables
  • You cannot delete base system tables. If you inadvertently delete such a table, it is automatically recreated when you upgrade an instance.
  • You cannot delete a table with associated tables extending from it.
  • Deleting all records for a table also deletes records from tables that extend the table

What is indexing in ServiceNow and its purpose?

  • Build indices to access the data held in your tables more easily.
  • An index puts unordered tables into order, and efficiently speeds up queries to columns in your tables, by creating pointers to where information is stored in your database.
  • Constructing an effective index requires specialized knowledge in database architecture

What are many to many relationships in ServiceNow?

  • Many-to-many relationships allow a list to point to a list of entries, rather than to a single field
  • The Many to Many Definitions [sys_m2m] table allows administrators to create custom many-to-many relationships.
  • Some many-to-many relationships are defined by default.
  • Administrators can enter the sys_collection list in the navigation filter to reference the many-to-many relationships available in the base system.

What is “task” table of ServiceNow?

  • Task [task] is one of the core tables provided with the base system
  • The Task [task] table provides a series of standard fields used on each of the tables that extend it, such as the Incident [incident] and Problem [problem] tables.
  • The Task table is a base class that provides fields for the core ITSM applications such as Incident, Problem, and Change Management.
  • In addition, any table that extends a task can take advantage of task-specific functionality for driving tasks.
  • Modifications made to the Task table are applied to all child tables.

What are journal fields in ServiceNow?

  • Journal fields work together to create a log of changes and comments as tasks are worked on.
  • Journal fields work on audited tables only.
  • Fields of the journal_input type are multi-line text boxes which, upon saving, add the comments into the Activity field with a notation
  • Two fields in ServiceNow are journal fields – Additional Comments and work notes.

What is a remainder table in ServiceNow?

  • The Reminder [reminder] table provides a way to auto-generate reminders for a task.
  • Any table that extends the Task table, such as the Incident [incident] table, can use the
  • Reminder [reminder] table.
  • You can add Reminders as a related list to the Incident form by opening the form context menu, navigating to Configure > Related Lists, and adding Reminders->Task.
  • By default, only an administrator can create or modify a Reminder record.
  • To enable non-administrators to create reminders, add create and read ACL rules to the Reminder [reminder] table and specify the user’s role.
  • To access the Reminder table, type reminder.do in the filter navigator.

What are assignment rules in ServiceNow?

  • The instance can automatically assign a task to a user or group based on pre-defined conditions using data lookup and assignment rules.
  • The Assignment rules module allows you to automatically set a value in the assigned_to and assignment_group fields when a set of conditions occurs.

What is the execution order between data lookup, assignment, and business rules?

  • Before business rules: Scripts configured to execute before the database operation with an order of less than 1000.
  • Before engines. The following are not executed in any specific order:
    • Approval engine (for task and sys_approval_approver tables)
    • Assignment rules engine (for task tables)
    • Data policy engine
    • Escalation engine
    • Field normalization engine
    • Role engine – keeps role changes in sync with sys_user_has_role table (for sys_user, sys_user_group, sys_user_grmember, and sys_user_role tables)
    • Execution plan engine (for task tables)
    • Update version engine – creates version entry when sys_update_xml entry is written (for sys_update_xml table)
    • Data lookup engine inserts or updates
    • Workflow engine (for default workflows)
  • Before business rules: Scripts configured to execute before the database operation with an order greater than or equal to 1000.
  • The database operation (insert, update, delete)
  • After business rules: Scripts configured to execute after the database operation with an order less than 1000.
  • After engines. The following are not executed in any specific order:
    • Label engine
    • Listener engine
    • Table notifications engine
    • Role engine – keeps role changes in sync with sys_user_has_role table (for sys_user, sys_user_group, sys_user_grmember and sys_user_role tables)
    • Text indexing engine
    • Update sync engine
    • Workflow engine (for deferred workflows)
    • Trigger engine (for all Flow Designerflows)
  • Email notifications. The following are executed based on the weight of the notification record:
    • Notifications sent on an insert, update, or delete
    • Event-based notifications
  • After business rules (Only active records), scripts configured to execute after the database operation with an order greater than or equal to 1000.

What are database views in ServiceNow?

  • A database view defines table joins for reporting purposes.
  • For example,
    • a database view can join the Incident table to the Metric Definition and Metric Instance tables. This view can be used to report on incident metrics and may include fields from any of these three tables.
  • Any user creating a report can use database views as the report source, but ACLs on the underlying tables are honoured.
  • A database view is not treated like a custom table, so no licensing impact exists.
  • Database view tables are not included in FTP exports.
  • You do not need to create ACLs on fields in the view. The system honours contextual ACLs (ACLs with a condition or script) on the underlying table.
  • Non-contextual ACLs (ACLs with only role checks) are still honoured, just as with previous releases.

What are the limitations of Database views in ServiceNow?

  • Database views cannot be created on tables that participate in table rotation.
  • It is not possible to edit data in the database view output.
  • Database view tables cannot be added as a data preserver in clone requests
  • You can still create additional ACLs on the database views. These ACLs are evaluated last and are always honoured.

How are tables related to each other in ServiceNow?

Tables can be related to each other in the following ways

  • Extensions: A table can extend another table.
  • One-to-Many: There are 3 types of one-to-many relationship fields
    • Reference Field: allows a user to select a record on a table defined by the reference field.
    • Glide List: allows a user to select multiple records on a table defined by the glide list
    • Document ID Field: allows a user to select a record on any table in the instance.
  • Many-to-Many: Two tables can have a bi-directional relationship so that the related records are visible from both tables in a related list.
  • Database views: Database views enable virtual joining of two tables to report on data that might be stored in more than one table.

What is sys ID in ServiceNow?

  • Each record in an instance is identified by a unique 32-character GUID (Globally Unique ID), called a Sys ID (sys_id).
  • When created within the application, sys_id values are unique.
  • The same sys_id value is never generated twice, ensuring that every record created in every table in every instance has a unique identifier.
  • A new record has a sys_id of -1, and once inserted, it is assigned a new sys_id.
  • The sys_id is not meant to show as a field on a form or as a column in a list.

When two records have the same sys_id in ServiceNow?

If two records have the same sys_id value, it occurs as a result of the following situations

  • If a record with the sys_id was copied to the other at the database level outside of the Now Platform.
  • If a record with the sys_id was copied using an Update Set or via XML, its sys_id is the same.

What is data archiving in ServiceNow?

  • Data archiving involves managing table size growth and archiving old data.
  • It moves data that is no longer needed every day from primary tables to a set of archive tables.
  • The longer an instance runs, the more likely it is to accumulate data that is no longer relevant. For example, task records from two years ago are typically less relevant than currently active tasks.
  • Old data may eventually cause performance issues by consuming system resources and slowing down queries and reports

Can we query the archived table in ServiceNow?

  • Archived tables are not optimized for ad hoc queries.
  • They only contain index entries for the display value, creation date, and the primary key of sys_id.
  • For this reason, do not make on-demand queries against an archived table, such as searching for all priority 1 archived incidents.
    • Instead, only search against the indexed fields.
    • For example, search for incident INC100001 or incidents created on a specific date.

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