Create and manage derived fields

Derived fields let you add computed columns to your asset dataset. For more information, see About derived fields.

Prerequisites

• View permission (required for all derived field actions)
• Create permission to add new derived fields
• Edit permission to modify existing derived fields
• Delete permission to remove derived fields

Contact your Lansweeper administrator if you don't have the necessary permissions.

Create a derived field

1. Go to Dashboard.
2. Select Create dashboard or select the dashboard you want to edit and select More actions > Edit.
3. Select Create derived field.
4. Enter a name in the Name field.
5. Optionally, enter a Description to explain what the field calculates and when to use it.
6. Write your expression in the expression editor. See Use the expression editor for guidance on the editor's features.
7. Select Save.

The derived field is now part of the asset dataset and can be added to dashboards like any other field.

Use the expression editor

The expression editor gives you a structured environment for writing and testing derived field expressions.

Browse functions and fields

The left panel has two tabs:

• Functions — Browse available functions grouped by category. Drag and drop or type the function to add it to the expression. Hover over a function name to see its description and type signature.
• Fields — Browse the asset dataset fields you can reference in your expression. Drag and drop or type the field to add it to the expression.

Write an expression

Enter your expression in the editor area on the right. As you type:

• Syntax highlighting distinguishes field references, function names, operators, and literals.
• Autocomplete suggests completions as you type. Select a suggestion to insert it.
• Inline validation flags errors with a red underline.

Field references use square brackets around the field name: [assetName], [diskDrives.size]. If a field name contains spaces, use its exact display name: [Last successful scan], [Warranty end date].

For a full syntax reference, see Derived fields expression language reference.

Preview your expression

A preview of your expression shows the calculated value for each sample row, so you can confirm the output before saving.

If the expression contains errors, the preview won't run. Fix the flagged issues in the editor.

Edit a derived field

1. Go to Assets > Fields > Derived fields.
2. Find the derived field you want to update.
3. Select ... > Edit.
4. Make your changes in the Edit derived field dialog.
5. Select Save.

Delete a derived field

1. Go to Assets > Fields > Derived fields.
2. Find the derived field you want to update.
3. Select ... > Delete.
4. Select Delete to confirm the deletion.

Next steps

• Derived fields expression language reference
• Derived fields function reference