Metadata

What is Metadata?

Overview

Metadata is information that describes your data - essentially “data about data”. Just as a book has a table of contents to help you understand its structure, metadata provides context about your data’s content, origin, purpose, etc., making it easier for you to find and manage information in your knowledge base.

This guide aims to help you understand metadata and effectively manage your knowledge base.

Core Concepts

• Field: The label of a metadata field (e.g., “author”, “language”).

• Value: The information stored in a metadata field (e.g., “Jack”, “English”).

Field name and value

• Value Count: The number of values contained in a metadata field，including duplicates. (e.g., “3”).

Metadata field

• Value Type: The type of value a field can contain.

  • Dify supports three value types:

    • String: For text-based information

    • Number: For numerical data

    • Time: For dates/timestamps

Value type

How to Manage My Metadata?

Manage Metadata Fields in the Knowledge Base

You can create, modify, and delete metadata fields in the knowledge base.

Any changes you make to metadata fields here affect your knowledge base globally.

Get Started with the Metadata Panel

Access the Metadata Panel

To access the Metadata Panel, go to Knowledge Base page and click Metadata.

Entrance of Metadata Panel

New metadata

Built-in vs Custom Metadata

Feature	Built-in Metadata	Custom Metadata
Location	Lower section of the Metadata panel	Upper section of the Metadata panel
Activation	Disabled by default; requires manual activation	Add as needed
Generation	System automatically extracts and generates field values	User-defined and manually added
Editing	Fields and values cannot be modified once generated	Fields and values can be edited or deleted
Scope	Applies to all existing and new documents when enabled	Stored in metadata list; requires manual assignment to documents
Fields	System-defined fields include: • document_name (string) • uploader (string) • upload_date (time) • last_update_date (time) • source (string)	No default fields; all fields must be manually created
Value Types	• String: For text values • Number: For numerical values • Time: For dates and timestamps	• String: For text values • Number: For numerical values • Time: For dates and timestamps

Create New Metadata Fields

To create a new metadata field:

1. Click +Add Metadata to open the New Metadata dialog.

New metadata

1. Choose the value type.

2. Name the field.

Naming rules: Use lowercase letters, numbers, and underscores only.

Value type

1. Click Save to apply changes.

Save field

Edit Metadata Fields

To edit a metadata field:

1. Click the edit icon next to a field to open the Rename dialog.

Rename field

1. Enter the new name in the Name field.

Note: You can only modify the field name, not the value type.

Rename field

1. Click Save to apply changes.

Note: Field changes update across all related documents in your knowledge base.

Renamed field

Delete Metadata Fields

To delete a metadata field, click the delete icon next to a field to delete it.

Note: Deleting a field deletes it and all its values from all documents in your knowledge base.

Delete field

Edit Metadata

Bulk Edit Metadata in the Metadata Editor

You can edit metadata in bulk in the knowledge base.

Access the Metadata Editor

To access the Metadata Editor:

1. In the knowledge base, select documents using the checkboxes on the left.

Entrance of Edit Metadata

1. Click Metadata in the bottom action bar to open the Metadata Editor.

Edit metadata

Bulk Add Metadata

To add metadata in bulk:

1. Click +Add Metadata in the editor to:

Add metadata

• Add existing fields from the dropdown or from the search box.

  

  Existing field
• Create new fields via +New Metadata.

  New fields are automatically added to the knowledge base.

  

  New metadata field
• Access the Metadata Panel to manage metadata fields via Manage.

  

  Manage field

1. (Optional) Enter values for new fields.

Value for field

The date picker is for time-type fields.

Date picker

1. Click Save to apply changes.

Bulk Update Metadata

To update metadata in bulk:

1. In the editor:

• Add Values: Type directly in the field boxes.

• Reset Values: Click the blue dot that appears on hover.

  

  Reset values
• Delete Values: Clear the field or delete the Multiple Value card.

  

  Multiple values
• Delete fields: Click the delete icon (fields appear struck through and grayed out).

  Note: This only deletes the field from this document, not from your knowledge base.

  

  Delete fields

1. Click Save to apply changes.

Set Update Scope

Use Apply to All Documents to control changes:

- **Unchecked (Default)**: Updates only documents that already have the field.

- **Checked**: Adds or updates fields across all selected documents.

Apply all changes

Edit Metadata on the Document Details Page

You can edit a single document’s metadata on its details page.

Access Metadata Edit Mode

To edit a single document’s metadata:

On the document details page, click Start labeling to begin editing.

Details page

Start labeling

Add Metadata

To add a single document’s metadata fields and values:

1. Click +Add Metadata to:

   • Create new fields via +New Metadata.

   New fields are automatically added to the knowledge base.

   

   New fields

   • Add existing fields from the dropdown or from the search box.

   

   Existing fields

   • Access the Metadata Panel via Manage.

   

   Manage metadata
2. (Optional) Enter values for new fields.

Values for fields

1. Click Save to apply changes.

Edit Metadata

To update a single document’s metadata fields and values:

1. Click Edit in the top right to begin editing.

Edit mode

1. Edit metadata:

   • Update Values: Type directly in value fields or delete it.

   Note: You can only modify the value, not the value name.

   • Delete Fields: Click the delete icon.

   Note: This only deletes the field from this document, not from your knowledge base.

Edit metadata

1. Click Save to apply changes.

How to Filter Documents with Metadata?

See Metadata Filtering in Integrate Knowledge Base within Application.

API Documentation

See Maintaining Dataset via API.

FAQ

• What can I do with metadata?

  • Find information faster with smart filtering.

  • Control access to sensitive content.

  • Organize data more effectively.

  • Automate workflows based on metadata rules.

• Fields vs Values: What is the difference?

Concept	Definition	Characteristics	Examples
Metadata Fields in the Metadata Panel	System-defined attributes that describe document properties	Global fields accessible across all documents in the knowledge base	Author, Type, Date, etc.
Metadata Value on a document’s detail page	Custom metadata tagged according to individual document requirements	Unique metadata values assigned based on document content and context	The “Author” field in Document A is set to “Mary” value, while in Document B it is set to “John” value.

• How do different delete options work?

Action	Steps	Impact	Outcome
Delete field in the Metadata Panel	In the Metadata Panel, click delete icon next to field	Global - affects all documents	Field and all values permanently deleted from the knowledge base
Delete field in the Metadata Editor	In the Metadata Editor, click delete icon next to field	Selected documents only	Field deleted from selected documents; remains in the knowledge base
Delete field on the document detail page	In the Edit Mode, click delete icon next to field	Current document only	Field deleted from current document; remains in the knowledge base