Field Clear Map
Removes data from a specified field by setting its value to null during work item migration.
Clears a target field by setting its value to null, useful for removing data from specific fields during migration.
The FieldClearMap is used to explicitly clear a field value on migrated work items by setting the target field to null. This is especially useful for sanitising or removing unwanted metadata, calculated fields, or legacy data that should not be carried into the target system.
Purpose and Use Cases
This map is typically used when:
- You want to remove confidential or obsolete field values from the target.
- You’re migrating to a system where a field is no longer in use or read-only.
- A field value causes validation errors in the target and should be reset.
Options
topBehaviour
- Clears the value of the specified
targetFieldby setting it tonull. - Executed before saving the work item to the target.
- Only affects the latest revision unless the processor is configured to rewrite history.
- Will silently overwrite any existing value in that field on the target.
Practices
- Ensure that the
targetFieldis writable in the target project. - Use this map only when you intentionally want to remove data; it will override any mapped or default value.
- Combine with
ApplyToto limit field clearing to specific types where the field is present. - Be cautious when clearing system fields; not all fields accept
nullvalues.
Limitations
- Does not validate whether the field actually exists on the target.
- If
targetFieldis a required field in the target process, this may cause a validation error. - Does not support conditional clearing; the field is always cleared if this map applies.
Samples
topSample
Sample
{
"MigrationTools": {
"Version": "16.0",
"CommonTools": {
"FieldMappingTool": {
"FieldMaps": [
{
"FieldMapType": "FieldClearMap",
"ApplyTo": [
"SomeWorkItemType"
],
"targetField": "Custom.FieldC"
}
]
}
}
}
}Defaults
Defaults
{
"MigrationTools": {
"Version": "16.0",
"CommonTools": {
"FieldMappingTool": {
"FieldMaps": [
{
"FieldMapType": "FieldClearMap",
"ApplyTo": [
"*"
]
}
]
}
}
}
}Classic
Classic
{
"$type": "FieldClearMapOptions",
"targetField": "Custom.FieldC",
"ApplyTo": [
"*",
"SomeWorkItemType"
]
}Metadata
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Created and maintained by Martin Hinshelwood of nkdagility.com
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