difference between general data types and ServiceNow field types?

[KM SN]

Question may seem fundamental or silly but need thoughts on it.

[AshishKM]

HI @KM SN ,

ServiceNow data type is mainly combo of database type and custom html type.

like in Database , integer, float , char , string , boolean where ServiceNow data types design to full fil db requirement along with form base needs.

like ServiceNow select box type  ( html select )  is pointing to Question Choice table where the Label/Value are string ( txt ) type. 

if u have any specific case or data type please share the details.

-Thanks

[Community Alums]

Hi @KM SN ,

Several field types are available in the system.

This table shows field types and corresponding MySQL database types. Typically, it isn't necessary to perform any actions at the database level. To learn about changing a field type, see System dictionary.

Database field types

Field types	Options	Dictionary XML type	MySQL DB type
String	small	string	VARCHAR(40)
String	medium	string	VARCHAR(100)
String	large	string	MEDIUMTEXT
String	extralarge	string	MEDIUMTEXT
Decimal		decimal	Decimal (15,2) older instances may have (12,2)
Integer		integer	Integer
True-False		boolean	TINYINT(1)
Date		glide_date	DATE
Date-Time		glide_date_time	DATETIME
Time		glide_time	DATETIME
Duration		glide_duration	DATETIME
Choice		string	VARCHAR(40)
Suggestion		string	VARCHAR(40)
Journal		journal	MEDIUMTEXT
Reference	<reference table>	reference	VARCHAR(32)
List		glide_list	MEDIUMTEXT
Url		url	MEDIUMTEXT
Image		user_image	VARCHAR(40)
Due-Date		due_date	DATETIME

Note: An example of option types is as follows:

• A string field defined in the platform with a max length of 40 characters → VARCHAR(40).
• A string field defined in the platform with a max length of x, where x = 41-255 characters, inclusive → VARCHAR(x) [examples: String 42 is VARCHAR(42) and String 211 is VARCHAR(211)].
• A string field defined in the platform with a max length of 256 and upwards → MEDIUMTEXT.

These field types are available to administrators when creating new fields or changing the type of existing fields.

Field types

Field Type	Description
Audio	Field for uploading and embedding .mp3 or .ogg audio files.
Choice	List of configurable choices.
Collection	Dictionary entries with the Collection type represent the table rather than a field on the table. Changes such as attributes or the Read only check box applied to this entry are applied to the table rather than a specific field. This entry is automatically created when a table is created. There should not be more than one entry for a table of this type.
Color	String field that accepts CSS color declarations (including hex or RGB notation) and displays a preview. To learn more, see https://developer.mozilla.org/en-US/docs/Web/CSS/color_value.
Condition String	Text field that accepts a plain JavaScript condition statement that is validated automatically for correctness before an update.
Conditions	Field that adds the condition builder to a form. You must specify a dependent field that references the table name.
Currency	Decimal field with four digits after the decimal point. When displayed on a form, a currency field also includes an additional choice list for selecting the currency type. If there is no default value for the field, empty currency fields use the reference currency. Adding a value causes the field to use the session currency of the active user. See Change default currency decimal places for how to use two fraction digits. Note: Once you assign this type to a field, you cannot change it to an FX Currency type.
Data Structure	Field that allows the selection of one of the following data structures and entry of values to organize particular information in the record. String Boolean Integer Decimal Object Array
Date	Day, which can be selected with a calendar widget.
Date/Time	Day and time of day, which can be selected with a calendar widget.
Decimal	Number with up to two digits after the decimal points (for example, 12.34).
Document ID	Reference to any record on any table.
Domain ID	System field that contains a reference to the domain.
Due Date	String input field that stores a date-time.
Duration	Length of time. A time stamp stored in the database as date time.
Encrypted Text	Field that is encrypted for security. Depending on the user's encryption module access, the field may be hidden, the value may be hidden, or the field and value may display.
Field Name	Reference field for a field name in the table selected in a Table Name field type. Make this field dependent on the Table Name field.
File Attachment	Field for holding a file. A field holds one file. All file types are supported.
Floating Point Number	Number with up to seven digits after the decimal point.
FX Currency	Also known in internal code as Currency2 fields, this field type is an alternative to the standard (default) currency fields found in most Now Platform® applications. This type of currency field is highly configurable, supports custom rate tables, report aggregations, and provides for improved visibility into conversion calculations. To learn more about the FX Currency field type, see Setting up and using FX Currency fields. Note: Once you assign this type to a field, you cannot change it to an Currency type.
Geo Point	Field for holding longitude and latitude coordinates.
HTML	String field with a built-in HTML editor.
Icon	String field that provides the user access to an icon picker in a form. By default, the favorites icon set is used.
Image	Field for uploading and embedding images.
Integer	Number with zero decimal points. Note: To search for an integer, input = followed by the integer in the search bar. For example, if you want to search for an Order of 100, input =100.
IP address	Variable character field that stores IPv4 and IPv6 addresses. See IP address field type for more information.
Journal	Field that accepts text entries and displays previous entries with a user name and time stamp.
Journal Input	Field that accepts text entries but does not display previous entries.
Journal List	Field that displays the contents of journal fields. You must specify the journal fields as the dependent fields. If a journal list field depends on more than one journal field, the entries are displayed chronologically.
List	Reference field that accepts multiple references rather than just one.
Long	Integer field that can contain a longer number than the integer field.
Name-Value Pairs	Field that maps text values. Each mapping is one-to-one, however a single Name-Value Pairs field can contain multiple mappings. Each mapping must use a unique name, and the name cannot be empty. For example, you can use a Name-Value Pairs field to hold header information for a web service request. In this example, the name of each mapping is the header such as Content-Type and the value is the header value, such as Application/json. For information on scripting Name-Value Pairs fields, see Name-value pairs field type.
Password (1 Way Encrypted)	Text field that stores passwords with one-way encryption. One-way encryption stores the password as a secure hash value that cannot be decrypted.
Password (2 Way Encrypted)	Text field that stores passwords with two-way encryption. Two-way encryption stores the password as a secure encrypted value that can be decrypted programmatically within the instance. You can use Password 2 encryption with form variables. To encrypt text fields on forms, use Password2 encryption with KMF. The length for password2 field values must be at least 255 characters.
Percent Complete	Decimal field that renders a percent complete bar in lists. You can convert any existing decimal field to a percent complete field.
Phone Number (E164)	String field that provides E164-compliant formatting and validation for telephone numbers.
Price	A currency field that enables control over conversions and display. See Price fields for more information.
Reference	Query that displays records from another table.
Script	Text field that accepts JavaScript code input and provides controls, such as syntax checking and formatting. It also provides a list of fields and server APIs. You must specify a dependent field that references the table name for the list of fields.
Script (Plain)	Text field that accepts JavaScript code input and provides controls, such as syntax checking and formatting.
String	For 255 characters or less, the string field is a single-line text field. Anything 256 characters or over appears as a multi-line text box. Note: The database may translate the value that you provide in the Max length field to the closest matching database field type. For example, a max string length of 80 maps to the nearest database field type of VARCHAR(100). For Oracle instances, users are not able to increase the max length of a string field to a value greater than 4000 through the application UI. Changes greater than 4000 require the CLOB data type in Oracle. If you require a field to be larger than 4000 characters, log an incident to request the change.
String (Full UTF-8)	String field that contains UTF-8 character encoding. This field type is restricted to the same maximum length that can be defined within the application UI as the String data type. Emojis are supported in the String (Full UTF-8) field type.
Suggestion	String field that provides suggested values but accepts free-form text. Available when you add a field by configuring a form or list. Otherwise, you must modify the dictionary entry of an existing string or journal field.
Sys ID	Field that contains a unique numerical identifier for each record. For more information about adding a Sys ID, see the following links: Add a Sys ID to a form. Add a Sys ID to a list. Danger: Modifying or deleting a Sys ID results in bad or lost data.
Table Name	String field that lets you select a table. If you use the Field Name field type, add this field type and make the Field Name field dependent on the Table Name field.
Time	Specific time. Stored in the database as a date/time field. Only the time part of this field is used. Note: This field always stores the date as 1970-01-01, which does not fall within the dates for Daylight Savings Time (DST). As a result, the time is not automatically adjusted for DST. If a custom feature uses time as a start time, it is the responsibility of the feature to adjust for DST, if necessary.
Translated HTML	HTML field that displays different translations that are based on the user's language.
Translated Text	Text field that displays different translations that are based on the user's language.
True/False	Boolean field that appears as a one-digit integer, typically 1 (true) or 0 (false).
URL	String field that is a clickable URL field when locked. Note: In the mobile UI, this field appears as a multi-line text field. The field saves as a single line, with the line breaks removed.
Video	Field for uploading and embedding video.
Wiki	String field with a built-in Wiki text editor that accepts a simplified version of standard Wiki text formatting.
Workflow	Choice list field that displays a stage in a workflow.

• Choice list field type

  A choice list is a type of field that lets the user select from a pre-defined set of choices.

• Condition field types

  A condition field specifies when to run business logic such as a business rule or workflow.

• Database field type

  Several field types are available in the system.

• Dictionary entry data types

  You can only change a dictionary entry's data type when the change does not result in data loss. Use the following guidelines to change a dictionary entry's data type.

• Document ID field

  You can create document ID fields to reference any record on any table.

• Function field

  Create function fields and scripts in the Now Platform to perform common database transformations and calculations.

• Geo point field type

  The geo point data type stores longitude and latitude coordinates.

• HTML field type

  The HTML editor provides WYSIWYG (what you see is what you get) functionality and HTML source mode editing. Administrators can customize some of the functionality associated with HTML fields.

• Image field type

  Image fields enable you to add images to forms.

• IP address field type

  The IP Address (Validated IPV4, IPV6) [ip_addr] field type stores valid IPv4 and IPv6 addresses.

• Journal field type

  There are three types of journal field: journal, journal_list, and journal_input.

• Name-value pairs field type

  You can access the values stored in a name-value pairs field in scripts using the name.

• Percent complete field type

  Administrators can create percent complete fields, which accept decimal input and appear as progress bars when displayed in lists.

• Phone number field type

  The E.164 phone number standard ensures that all necessary information for a phone number is included and properly formatted to successfully route an international call over a territory's public telephone network.

• Reference field type

  A reference field stores a reference to a field on another table. For example, the Caller field on the Incident table is a reference to the User [sys_user] table.

• Suggestion field type

  To help users find what they are looking for, you can add a suggestion field to any form.

• Wiki field type

  Wikitext fields use the basic wiki markup language and support links to external URLs and to sources within the system.