Field Types

SmartTable provides a rich set of field types across 9 categories. Each type is designed for a specific kind of data and comes with its own configuration options.

Field Type Overview

Category	Field Type	Description
Text Types	Single Line Text	Short text input with validation rules
Text Types	Long Text	Long text/paragraph input with multi-line editing
Text Types	Rich Text	HTML rich text editor with formatting support
Numeric Types	Number	Integer/decimal with number/currency/percent formatting
Date Types	Date	Date picker supporting multiple date formats
Date Types	Date Time	DateTime picker accurate to seconds
Selection Types	Single Select	Dropdown single select with custom options and colors
Selection Types	Multi Select	Tag-style multi select with custom options
Selection Types	Checkbox	Boolean toggle
People Types	Member	User selection with current-user default value
Contact Types	Phone	Phone number input and formatted display
Contact Types	Email	Email address input and validation
Contact Types	URL	URL link with click-to-navigate
Media Types	Attachment	File upload/download with image preview and thumbnails
Computed Types	Formula	47 built-in functions with field references and nested calculations
Relation Types	Link	Table relationships supporting one-to-one/one-to-many/many-to-many
Lookup Types	Lookup	Cross-table queries with aggregation (sum/avg/count/etc.)
System Types	Created By	Auto-record record creator
System Types	Created Time	Auto-record creation timestamp
System Types	Updated By	Auto-record last modifier
System Types	Updated Time	Auto-record last modification time
System Types	Auto Number	Auto-increment with prefix/suffix/date format/padding
Others	Rating	Star rating component
Others	Progress	Progress bar/percentage display
Geolocation	Geolocation	Structured province/city/district, country/region, or lat-lng coordinates, with map picking and multi-language support

Choosing a Field Type

Pick the type that matches how the data will be entered, displayed, and calculated. For example, use Single Select for statuses, Link for relationships, and Formula for computed values.

Changing the Field Type of an Existing Field

After a field is created, you can still change its field type. The system automatically determines the allowed conversion scope based on whether the field already contains data, and safely migrates existing values to avoid silent data loss.

1. Field has no data: free conversion

When a field has not yet been written to, it can be freely converted to any other type (subject to the universal restrictions below).

Empty-value rule: null, an empty string, or an empty array are treated as "no data"; 0 and false are valid business values and count as having data.

2. Field has data: lossless only (one exception: Date ↔ Date Time)

When a field already contains data, only lossless conversions are allowed — the target type must fully preserve the original value. Beyond that, exactly one lossy conversion is permitted:

• Date → Date Time: lossless — the time part is auto-completed (e.g., 2023-05-01 → 2023-05-01T00:00:00Z).
• Date Time → Date: lossy — only the date part is kept and the time part is discarded, unrecoverably. A confirmation dialog clearly states "the time part will be discarded and cannot be recovered" before the conversion can proceed.

All other lossy conversions are forbidden (e.g., truncating long text, dropping options when converting multi-select to single select, resolving references to names), so data is never changed unexpectedly without your knowledge.

3. Lossless conversion rules (field has data)

From	Can convert to	Data handling
Single Line Text	Long Text, Rich Text	Original value preserved
Long Text	Rich Text	Original value preserved
Single Select	Multi Select	Single value wrapped as array [value]
Email / Phone / URL / Barcode	Single Line Text, Long Text, Rich Text	Original string preserved
Number / Currency / Percent / Rating / Duration	Each other; or text types	Value preserved, only display format changes
Percent (Progress)	Number	Value preserved
Date	Date Time (with T00:00:00Z); or text types	Date / original value preserved
Member	Single Line Text, Long Text, Rich Text	Member ID preserved (no longer linked to a member)
Formula	Other types (frozen as a static value)	Current computed result is fixed and stops recalculating

When a reference type (Member, Single/Multi Select) is converted to text, the original ID string is preserved (strictly lossless). Resolving it to a name or option label is lossy and is never done; the UI shows a notice: "the ID is kept and the link to the member/option is removed."

4. Pre-conversion value compatibility check

Even when a conversion is on the allowlist, all existing values are validated against the target type before saving. If any record cannot be carried by the target type and cannot be migrated losslessly, the system rejects the entire conversion and returns the number of incompatible records plus samples — values are never silently rewritten or cleared.

5. Prohibited conversions

The following types are prohibited in both directions and appear greyed-out with a reason in the type selector:

• System-maintained types: Created By, Created Time, Updated By, Updated Time, Auto Number.
• Reference / computed types: Link, Lookup, Rollup, Button.
• Target is Formula: a formula requires an expression, so converting another field "into" a formula is forbidden.
• Primary field restriction: the primary field (used as the record title) may only be converted among text types. Exception: a primary auto-number field with data may be demoted to a text type (single/long/rich text); the reverse (primary text → auto-number) remains forbidden.
• Text → Phone/Email/URL: when a single/long/rich text field already has data, converting it to Phone, Email, or URL is forbidden, otherwise existing text may fail the target format validation and produce invalid data. (Empty fields are not restricted.)

For the full decision order, lossless/lossy allowlists, and reason mapping, see Field Type Conversion Rules.

Common Configuration

Most fields support the following settings:

• Field Name — Display name of the column.
• Field Description — Help text shown to collaborators.
• Required — Whether the field must contain a value.
• Default Value — Value applied automatically to new records.
• Validation Rules — Length, range, regex, or format checks.

Text and Numeric Fields

Single Line Text

Short text such as names or titles. Supports maximum length and regex validation.

Long Text

Multi-line text for descriptions and notes. Supports line breaks and Markdown rendering.

Rich Text

HTML rich text with formatting such as bold, lists, links, and tables.

Number

Integers or decimals. Configure decimal places, minimum/maximum values, and display format (number, currency, or percentage).

Date and Selection Fields

Date / Date Time

Choose dates or date-times from a picker. Support multiple display formats.

Single Select / Multi Select

Choose from predefined options. Set custom colors and default options. Multi Select displays values as tags.

Checkbox

A simple true/false toggle. Useful for completion flags.

People, Contact, and Media

Member

Reference system users or team members. Supports single or multiple selection and can default to the current user.

Phone / Email / URL

Validated contact fields. URLs are clickable and open in a new tab.

Attachment

Upload images, documents, and other files. Supports previews, thumbnails, and downloads.

PDF Preview

PDF attachments support an inline preview so you can read documents without downloading them:

• Double-click to open: Double-clicking a PDF attachment in a cell opens the preview dialog, which is always centered in the browser viewport regardless of whether the attachment column is scrolled out of view.
• Page-by-page rendering: Multi-page PDFs are stacked vertically and scaled to fit the preview area (standard A4 ratio). Scroll up/down to browse pages, with behavior matching the official pdf.js viewer.
• Zoom and rotate: Zoom in/out (±) and rotate pages to inspect details.
• Page navigation: Previous/next buttons and direct page-number input with smooth scrolling to the target page.
• Download: A download entry in the preview window lets you save the current PDF locally.
• Thumbnail and icon: PDF attachments show a centered "PDF" label icon in the cell for quick identification.

The previewer is powered by pdf.js and is ideal for contracts, scans, and report documents.

Computed and Relational Fields

Formula

Calculate values using 47 built-in functions. Reference other fields and nest functions for math, text, date, logic, and statistics.

{Unit Price} * {Quantity}

IF({Score} >= 90, "Excellent", IF({Score} >= 60, "Pass", "Fail"))

Link

Create relationships between records in the same or different tables. Supports one-to-one, one-to-many, and many-to-many relationships.

Lookup

Pull values from linked records and aggregate them with sum, average, count, and more.

System Fields

System fields are managed automatically:

Field	Purpose
Created By	User who created the record
Created Time	Timestamp when the record was created
Updated By	User who last modified the record
Updated Time	Timestamp of the last modification
Auto Number	Auto-incrementing ID with optional prefix, suffix, date format, and padding

Geolocation Field

Used to record structured geographic information. It supports cascading Chinese province/city/district selection, country/region selection, detailed addresses, latitude/longitude coordinates, and map picking, with Chinese/English switching that follows the interface language.

Key configuration:

• Choose an Address format when creating the field: Province, Province + City, Province / City / District, Province / City / District + Detail, Country / Region, Lat-Lng, Map Picker.
• Values are stored as a structured JSON object (with province/city/district/detail/country/region/lng/lat fields), making them easy to filter, aggregate, and export.
• Double-click a cell in the table view to edit inline; cascading formats (province/city/district, country/region) auto-commit when the last level is selected.

For detailed usage, per-format steps, address auto-recognition, multi-language, and map picking, see Geolocation Field.

Related Links

• Field Type Conversion Rules
• Link Field
• Lookup Field
• Formula Field
• Geolocation Field
• Table Operations
• Workflow Automation